I have to wonder if Adventure Girl is right. The good places I know of go *way* out of their way to make sure you get a helmet (in fact, they wouldn't let me out the door to test-ride a bike without loaning me a helmet), and they usually make a point of suggesting gear, and give you a discount on accessories bought at the same time as your bike.

Then again, I don't have years of experience with this, so maybe I've just been lucky.