As does auh2o, I often use curbside UA baggage check, then go to the RCC to get my boarding pass. It's lovely to be unencumbered as I stop in the bookstore and browse the shops (if there's time) and use the potty. However, I have learned it pays to make a quick detour INSIDE before using curbside baggage check to the monitor to ensure my flight is actually scheduled to depart more or less on soon (although usually not on time). During winter and almost always when one is flying to LAX, it's not unusual for flights to be canceled. I want to make sure my bags get on the same flight that's carrying me.

I like the curbside baggage guys at SFO/UA. They're fast, smart and don't take their tips (which they earn!) for granted.