This reminds me of that scene in Reservoir Dogs about the guy who wont tip waitresses, because 'it's their job' to provide the service etc etc...
Lately I have found, unfortunately, that curb side check-in at LAX in particular takes way too long. A lot of "non-medallion" or "non-F" pax have figured out that it is faster to wait at Curb Side than to go inside to the kiosks and bag drop for coach.
So at LAX at least, the curb side is no longer any benefit to me as an F pax or as a PM. First Class/Medallion check in is faster.
But, whenever I have used curb side, it is at least $3 a bag, sometimes $5 for 1 bag. I know those guys, I see them a lot (or at least I used to see them a lot, until it started getting crowded) and many of them recognize me when I do show up. I am not going to be known to them as the cheap guy.
Unfortunately, they do not have an F line for curb side. Maybe I should start tipping $20's and then they will see me when I get out of the car and let me skip the Curbside line. Now I know so many folks are cheap $20 should do it.
Now I have been to many other airports, TUL, ORD, MCO, etc etc and found that these airports, the sky caps are not as busy. Just my experience. But I still tip, $3 a bag at least. Same for the bell man in the hotel. $3 a bag minimum. AND I also tip the chambermaid.