Yours is an interesting assertion - restated (and tell me if you think I'm not accurately restating your position) that personal responsibility is a weak defense against irresponsible predators in the marketplace. I spent some time thinking about your proposition in light of recent events, but I believe you are underestimating your power to keep yourself out of trouble through prudent research.
While not an absolute defense, I disagree that personal responsibility isn't a strong defense against predators. Part of personal responsibility is evaluating the reliability of information. A used car salesman's estimate of his product's worth is much less trustworthy than Kelly Blue Book, for instance, because KBB isn't trying to get my money (other than the modest price of their information).
Similarly, when we bought our house, our mortgage broker offered to lend us twice what we were requesting so that we could buy a much nicer house. She assured us our income could support that size of a mortgage. Tempting.
Independent recommendations, however, showed we were seeking the right size mortgage. I trusted their advice more than the broker's because they did not stand to benefit if I took their advice. This was a prudent assessment, and as a result, we aren't in trouble in the current financial mess.
So when you say "good people can be taken in by someone who they think they can trust", I would counter that "good people were taken in by someone they should have known better than to trust, but accepted their statements because they really, really wanted them to be true". It's certainly human nature, and I support Truth in Lending laws and such - but ultimately, you're much better off to "trust but verify" in your financial dealings rather than hoping laws will protect you from your own over-enthusiasm.
While I agree that personal responsibility isn't a panacea for avoiding financial errors, it's the best defense I know. If you don't expect the government, or your parents, or FDIC, or anybody else to bail you out of your mistakes, you'll be more conservative in financial affairs - and that's a recipe for success in most cases, AFAICT.
Regardless, I appreciate the thoughtful response.