If renee regrets for not giving her numbers to her old regulars from Peony, it doesn't make sense. If she is busy at SL, she would not have the time to meet up with all the demands. If it was slow, then this is where people start thinking of how to keep themselves busy.
It seems there are a few and far between clients that would tip very generously(or stupid) but it is not common. If it was, then I hate to say this , there is no reason to get excited by advertising how a customer came in and gave many brownies.