If you enter a pin number, then they don't need a signature. Only if you're using it as a credit card, otherwise they don't bother.

A lot of places do this now. If your charge is less than $25.00 they don't require a signature. It's the idea that, sure, someone COULD challenge the charge and say, "That's a fraudulent charge - I never signed for it." and they'd probably be reimbursed for it, but very few people would ever even try that, and the time that it saves in lines of people when each individual person doesn't have to sign for their charge is huge. So basically, for business, it's a cost-benefit analysis.

Kind of similar to this... I had the bank cash a check that wasn't signed or endorsed. They told me they get so many checks they can't possibly LOOK at them all.

starbucks does the same thing