However, one could argue that such an agreement would only represent a codified social contract. Ie it's still "You aren't holding up your end of the bargain" rather than "the contract is for 2 hours/day with an optional extension of $100/hour each day."

Parking an old, windowless, van just off the day care property may reinforce the need to increase the priority of picking up your offspring.

It may also incentivize customers to change day care.

You may not know - but there's a massive shortage of day care and lots of government regulation.