Just for the sake of accuracy, it's 2.5 hours to "report for duty".

At SFO, for example, from the time you swipe into the Employee lot, it is at least 20 minutes to get to Ops or the gate/aircraft. And that's moving at a good pace.

I've taken advantage of contractual provision of parking closer to the terminal with a short call out. I haven't timed it, but I'd guess it only saves 5'-8' tops.