[methodover]

I think there's an aspect of morality that you're missing. There comes a moment when taking advantage of someone's lack of foresight, lack of intelligence, and/or carelessness becomes immoral.

I'm not sure where exactly that line lies, but I think I have a good staring place:

If you've created a system that takes someone's money -- even when that transaction was done with the person's prior permission in some way -- and that person says "Woah, wait a minute, this isn't what I thought I signed up for," that's a hint that you might be on the wrong side of that line.

If millions of people have that reaction, and legislators start making public inquiries into what you're up to, that's a REALLY good sign that you might be on the wrong side of the line.