Unless you're in a really dysfunctional startup, the employees who voluntarily jump in after-hours to fix OC issues are going to be very quickly compensated with raises and refresher option grants. Far better payout generally than a few bucks of overtime.

It becomes really obvious who is holding the company together and who is coasting, relying on the "senior" (ie, anyone who puts in the effort) engineers to keep the ship afloat, and in a highly competitive engineering market, that will definitely be reflected in equity comp.