I do my normal shopping at a large and busy grocery store near the centre of Auckland. There are no turnstiles or even those flappy "gates" that let you pass in just one direction; the entrance is completely open. Quite often I walk in before realising I need to get a basket from outside, so I go back and get one. On several occasions I've changed my mind and left before venturing too far into the store. Nobody cares.

That said, if I had spent any significant time in the store without getting anything, I'd probably leave by the self serve checkouts.