Would you like a bag for that at all?It seems to be one of those über-polite cashier usages, and to mean something like 'Would you have any interest at all in a bag?' I don't know about nationally, but around here that's just pervasive usage, and it's spread well beyond the service encounters were she, I think, first noticed it.
Last night at dinner, someone was talking about her new book (not in linguistics, sadly) and said:
I hope it sells at all.My immediate reaction was that it was like positive anymore ('gas is expensive anymore', etc.'): What used to be used only in negative contexts has broadened to include a positive reading. (I'm pretty sure this person has positive anymore.) But I chanced to talk to Monica about it this morning and she reminded me of the 'service at all'.
Maybe two pressures pushing in the same direction?