"If I were a plugin author of a somewhat popular plugin and I saw it being used on a number of high profile, income generating websites, I would certainly be miffed if I didn’t see sizable donations arriving in my paypal account from those sites."

Well... when you release something for free, it means.. FREE. As in, you're not gonna get paid. :) Regardless of who uses it or where it winds up. Saying that implies that once you (not you specifically, general you) put something out there, if it becomes wildly popular, then you *should* get paid for it.

And that's not what it's about at all.