Seriously, with any new policy, there seems to be a social aspect in which the policy is taken seriously at first, and then things slide back to the way they were. Just don't push the envelope too much, but some reasonable chance that after a week or two, you could stretch the break to 20 minutes without anyone saying anything, and just forget about the time deducted for something as normal and human as going to the restroom, for crying out loud!
With Walmart cashiers in a store, the computer will saying "approaching lockout" at 5 and a half hours. And at 5:45 will not let the cashier start any new transactions. And supposedly, cashier will get in trouble if they don't clock out for meal break by 6 hours. Meaning, a 12 shift may be bumping against this, but Walmart warehouses may be different.