In that case, they may have just been lucky to have a cop nearby, but for some other reason, not for you. Like I said, I can't see how there'd be enough time for the cop to get there for you if they call them after you pass last point of sale.

And if this is your first time at this store, then they clearly broke operational rules if they called the cops before you passed last register. Not suprising or unheard of but rare because even in those cases cop response times are too long to do any good. We're not talking 911 calls or armed robbery.