Ethics and legality don't always align. You will always find people who are willing to push the ethical line a bit further out to satisfy their greed. Then of course, it's not too much further to meander across that legal line as well.

What can government/regulators do? If they respond harshly and abruptly, they are criticized as being too heavy handed, and enemies of capitalism. If they respond slowly and deliberately, they are called slow and ineffective.