Turnover is already high due to shitty work conditions and low pay, but most franchises will also look for reasons to fire so they can keep wages low.

A few minutes later than the customer wants but still within reasonable time? Oooh sorry they called to complain so we have to give you a strike.

Customer doesn't want to pay? Tough shit, you shouldn't have given them the pizza without getting paid and that's two strikes.

You were 30 seconds late according to the managers watch which is 3 minutes fast as proven by everyone's cellphones and the wall clock? Too bad, fired.

And I'm not exaggerating. I'm just giving a real-world example.