But there is nothing to stop you buying the parts from the local hardware store, and I never heard of anyone being prosecuted.

Of course, if the insurance company finds out your house burned down because of your dodgy electrical work, good luck making a claim.
If someone died in the fire, good luck in gaol.

In other news, "the world" recently found to consist of only the UK and Australia.

Reducing the BAC to 0.05 and implementing random breath testing has been very effective in reducing road deaths. We reduced the BAC limit to 0.05 in the 90's and this is why Australia has 5.7 deaths per 100,000 people (8 per 100,000 vehicles) and the US has 12.7 deaths per 100,000 people (15 per 100,000 vehicles). Because it sure as shit isn't because Australian's can drive.
For reference, Victoria introduced a 0.05 limit in 1966, NSW in 1980 and Qld in 1985. I'm not sure about the other states, but the only one I can imagine holding out until the '90s would have to be the NT.
It's interesting to hear older folks talk about drink driving in their youth, however. My father (now in his late 60s) worked in insurance and used to do a lot of driving in western Queensland. His habit after finishing his rural appointments was to buy a carton of beer and start the 2-3 hour drive home - he reckons most times he'd be 1/2 to 2/3 through it by the time he rolled into the driveway.
Of course, the roads were a lot emptier back then as well, which probably saved a lot of lives.

Anyone who drinks regularly is like not that impaired at those levels. If I am as impaired at 0.1 as you are are at 0.05 why can I not drive at 0.1?
Because laws aren't personalised.

The introduction of RBTs ("Random Breath Test" stations - basically a roadblock where large numbers of vehicles are stopped and drivers tested) in Australia led to a significant reduction in road fatalities.
Source.

At the same time, a 0 limit means you'd pretty much have to avoid all substances with trace amounts of alcohol, which would be difficult from a practical standpoint. Start looking at how many brands of mouthwash and similar products contain alcohol, and you'll see what I mean.
In Australia (and I imagine, most other countries) the breath test is not what gets you charged, it's the blood test that follows. This prevents the mouthwash problem.

You put a cap on how much they can spend on political donations (including advertising). Ideally one within reach of the typical person (say, 1% of median income, or the equivalent of two weeks worth of minimum wage).
Then, everyone can still say whatever they want, but being rich doesn't automatically give you the ability to yell louder than everyone else. If you want to be loud, you need to convince a lot of people to yell the same thing you are.

It would be pretty starling if you weren't allowed to exercise these rights in concert, for example by assembling into a corporation and lobbying or contributing to a campaign.
Capping any individual's contribution to, say, $10/yr would not infringe those rights, it just attempts to ensure the person with a billion dollars to spare doesn't get any more attention than the person with ten.

The hard part is deciding what 'appropriate levels' might be for any given political election [...]
Better to attack it from the sourcing side and let the people decide.
Campaign contributions should be limited to natural persons, and to a maximum of two weeks worth of full-time minimum wage labour.
That way good ideas can still attract large amounts of funding, but bad ideas that appeal to a minority of very wealthy individuals cannot.

So let me get this straight. You want to have a third party threaten everyone with violence in order to get everyone to turn over a percentage of their property so that the third party can keep most of it for themselves and then redistribute a small portion of it with the net result being that almost everyone is poorer than they would have been. This is what you want?
People who wonder what a Straw Man argument is, should read the above quote.
And where did you get that this is the only way that serfdom can be prevented?
History. The greedy and powerful are incapable of self-regulating.
In the early part of the past century the trajectory of the American working class was moving up - and fast. Then the third party decided to fix it.
The single most prosperous period of human history was post-WW2 America. Right up until the early '70s when the neo-liberals took over and started implementing policy to concentrate wealth, eliminate the burgeoning middle class, and slam the brakes on social mobility. Since then, as the GP noted, the vast majority of productivity and wealth increases have gone to an increasingly small section of society.

I escaped from poverty on my own, without someone else paying my way.
So no public schooling ? Never taken a dime of welfare ? Parents never on welfare ? Never taken public transport ? Never called the police ?
I really can't stand when some prick like you acts like its impossible for someone to pull themselves out of the slums in America. This isn't fucking Kenya. In America, contrary to what all you Occupy Wallstreet douchebags with your North Face backpacks and tents think, you make your own way in this place.
America is one of the least socially mobile societies in the civilised world.

Getting online and telling people that civil rights will suddenly go away because of this film is an attempt at censorship and it is the reason why we have the Freedom of Speech in the first place.
By your logic, "getting online" and telling people they shouldn't shop at $STORE because it sucks, would be theft.

Some are even so strict as to try to "mask" the tax rate by not allowing sellers to show with-tax prices before the sale transaction begins. This is why we don't have more stores that say "this item is $5.00, tax included". This is an asinine bureaucratic requirement that needs to be removed and the people who invented it, continued to enforce it, and who support it idealogically dragged out into the street and publicly humiliated and executed.
Meanwhile, one of the most frequent complaints from visitors to the US is that advertised prices don't include the tax component, to them representing a form of false advertising.

I don't think they can force sellers outside of the USA to charge US state sales tax to their customers so I guess I will be buying some stuff 'offshore'
Maybe at that point the reality of America being one of the cheapest, lowest-taxing countries in the western world might sink in.

What do so many Americans have such fear/hatred of Socialism?
Because they don't understand what a false dichotomy is.