Unfortunately they do enhance security a little, although I strongly believe the enhanced security doesn't actually make anyone safer. I look at this way I could hire a virtual army of body guards to patrol outside my house and I'll be pretty safe from a break in. But that level of protection against something that's extremely unlikely to happen is just retarded. Terrorist some day will probably succeed in killing more Americans in our home country... however spending billions of dollars and completely destroying our privacy isn't justified by the possible death of even a couple of thousand people.
Oh and what these devices are really meant to detect are deadly things that a metal detector or sniffer can't detect. Such as broken glass, a true ceramic knife (most of them have metal in them purely to be detectable by metal detectors), or even a sharp stick (or pencil... wonder when they'll be banned). Keep in mind that any of these items could have been used by the 911 terrorist and would have been almost effective (if not as effective) as the box cutters they used.
The feds and specifically TSA are really just trying to see how much they can get away with before the public complains. I fully expect, (if these things are allowed to stay) that in five years you won't be allowed to have any liquids (acid can be really dangerous), batteries, pencils, pens or, shoelaces (can be very effective to strangle someone with). What we'll be left with eventually will be a plane full of people in their underware reading books... oh wait... I've had some nasty paper cuts before
I'm not sure if this is what your referring to but I use a SSH socks proxy and tsocks under linux quite a bit to allow proxy unaware apps to be use it (like RDP). The only issue I have with this setup is DNS. Since it primarily uses UDP not TCP for lookups they are all performed against the locally configured name servers not the remote. I haven't found an elegant solution for this yet but your network.proxy.socks_remote_dns config may help a lot (I've never heard of that before).
For the original submitter, I understand your reluctance to being restricted and object to the idea of the great firewall as much as the next guy, however is completely open access really worth breaking the law there and potentially being imprisoned in China. Also keep in mind that while you may object to the concept of the firewall but you are a guest in the country and breaking any countries laws while as such is really disrespectful. If you really don't like the law don't travel there, if your trying to make some sort of political statement (which I doubt) then best of luck to you... China isn't well know for being good sports about that sort of thing.
As someone who spends a lot of time around Mexico City (my wife's family lives there) I'd love to buy one of these for each of my kids. There are far too Americans getting kidnapped in that area for someone to argue that it's not worth the price. Of course it probably wouldn't take long for a kidnapper to find it and get rid of it, but if it takes 30 minutes that may be enough time.
And additional FYI, they aren't just kidnapping the rich anymore. Now they've resorted to kidnapping for several thousand dollars which makes anyone in that area very vulnerable.
"Ninety percent of baseball is half mental." -- Yogi Berra