You seem to forget that grandparent is British...

Actually the above firewall rules only block access to the web server, telnet server and ssh server running on the router itself, not the forwards to the Internet (the rules are appended to the INPUT chain, not the FORWARD chain).

That would be kind of stupid anyway, because the user would notice this rather quickly, and probably power cycle the router because his Internet doesn't work. Kinda pointless to make it obvious there is something wrong when your goal is to run a botnet...

Second, I've found instances of warranties for Netherlands products that state that you need to go through the manufacturer (search Google for netherlands warranty and read a few till you find them) which would indicate you are incorrect.

Yes, they may claim that, but if push comes to shove they'll have to deal with it themselves. You can basically ignore such statements. Most websites of consumer organisations have a section about it, like this one. The above website mentions 3 kinds of warranties: sellers warranty (the one you refer to), manufacturers warranty and legal warranty.

Legal warranty states that you have a right to a "decent product" and that the seller is responsible for this. Normally you have to prove that your use of the product didn't cause the defect, but during the first 6 months the burden of proof is reversed: "A defect that occurs within 6 months of purchase of the product is assumed to have been present at the moment of sale."

Unfortunately most people don't know this, and let themselves be intimidated by the sellers. Fortunately there have been consumers and consumer organisations that enforced this law through court, and there are more and more internet forums and television shows about this.

This also means dutch law has no fixed warranty times, instead it works under the premise of what can be "expected". An expensive washing machine can be expected to last a lot longer than the 1 year seller warranty that the store usually gives. So, if it breaks down after 2 years the retailer is still responsible for the repair or replacement.