Putting it on someones Profile page might get around that completely, what do you think?
That's the best idea so far.
I'm not sure about this whole idea. (My reaction to the original post was mostly for the post being funny.)
It's nice to have a simple option to show some appreciation to someone who helped for free.
OTOH, it will at least have some technical implications, though. Paying with PayPal is fairly easy, but this requires the person (supposed to be) receiving the money needs to have a PayPal account too.
Technicalities aside, will it be a disappointment for someone, who put in a lot of effort into helping, not receiving any coffee?
If multiple people helped someone who should get rewarded (how much) and who not (so much)? How to quantify?
This is an international forum. Someone's coffee might be someone else's hourly wage. - Will this have implications?
Yes, lot's of questions. - I'm afraid I have no answers, yet.