[sfrank2147]

That's a great tradition! From an economics perspective, I would gain way more than $2 worth of utility from discovering that someone had randomly paid for my coffee, it would really make my morning.

I wonder if the benefit would decrease if the practice became more common though. Would I start expecting my coffee to be free, and become disappointed when I had to pay for it?

[noobermin]

That assumes that it would have to happen more often than %50 of the time, which I think is impossible.