Don't think so, it was clearly marked with price list and everything.

I imagine it's more along the lines of "I'll pay them all by the end of the week/month", and then they forgot about it. Or perhaps sales grabbed a bunch to hand out to potential customers, assuming that the company would reimburse any losses.

Either way I don't think the high-income earners were deliberately cheating more than average.

But I think it is a point that the price of a candy bar looks like smaller and smaller change the more you earn, perhaps to the point were it seems irrelevant.