As an ex OO guy I have to chime in here. It's not United that is pushing this, it's your own company. UAL wants the on-time. They pay by the flight, not flight time. Many contracts pay whether the flight runs or not. Others pay less so your management needs to cut costs to make a profit. Your regional management pays you, the pilot, by the minute. They are the ones driving any cost savings inititiatives. By not paying you a few minutes here and there it saves millions per year.
Back when Skywest had only 700 pilots we manually filled out overtime sheets for each leg. Even if we only had one minute of overtime we would fax the pay sheet to headquarters. I personally overheard BH at a Christmas party in PDX say the company saved $1.5 million per year in overtime due to lazy pilots not sending in the overtime sheets. See, the captain had to send it in for the whole crew.
Skywest was growing like crazy now. The volume of faxes to headquarters grew and grew. Pilots were getting smarter about pay. Only one person in St. George was manning the overtime desk and was swamped. The company asked SAPA to ask the pilots to stop sending in overtime sheets for just one or two minutes. Personally knowing how much the company saved for each lost minute I was happy to see SAPA grow some nuts. They said they would agree but only if 10 minutes of credit was added to each leg. The company got the hint.
Long rant but my point is that each minute counts. Millions can be saved by screwing you, the pilot.