I saw a thread here or on CU, but didn't comment. IMO, if a restaurant wants to refuse service for something like that, that's their business choice - a foolish one, but theirs to make. In this case it's unclear whether the store manglement was aware of what (s)he did. It may be that (s)he hid what was done by taking their order, but @#$%-canned it rather than taking it to the kitchen.
Anyway, corporate reacted, after a lot of bad publicity. Reluctantly or willingly, who knows? I hope that little tantrum was worth losing a job, and maybe becoming less employable (who wants to hire as a server some one like that?!).