Earlier quoted context omitted.
and annoying. you're charging your most loyal users the cost of providing proof after all these years.
Or don't. Just ask users to tell you (without any burden of proof) if they've been paying less. Will a handful of users abuse this? Probably. My bet is that the vast majority are honest people -- particularly if the circumstances are clearly and simply communicated -- and will not take undue advantage. The upside is that you won't be pissing off the honest majority, and the cost is probably (admittedly un provably )…
what makes you believe this? feel like this is Hobbes vs Rousseau