pervocracy:

You can ruin almost any social system with enough bad faith.

It takes very little cleverness to go to a toilet with a sign reading “please do not flush paper towels,” flush gravel until it breaks, and then declare victory.

But victory over what?  You haven’t debunked the warning sign or the plumbing system; you’ve just abused them.  You have not made a persuasive case that the warning sign should read “please do not flush paper towels or gravel,” because obviously your wise ass is just waiting to see that sign so you have an excuse to flush a third inappropriate thing.  You also haven’t made a persuasive case that the toilets should be continuously guarded and all visitors frisked for non-flushable objects, because the vast majority of people aren’t as big of a jerk as you.

“This system can be broken by someone who exploits its rules in the most malicious possible way” is true of many otherwise fine systems, and unless the system is safety-critical or there’s a very large group of people motivated to break it, it’s not really an important point to make.

There is nothing original, helpful, or insightful about pointing out that one person with a firehose could ruin a whole sand-sculpture competition.  Yeah, it’s true, that is a risk we are taking.  Please don’t show up with a firehose just to prove your point.