It’s a ridiculous Americanism. Not the worst societal norm out there, but ridiculous, nonetheless.
I do enjoy the posters who infer that the drivers may threaten action in terms of providing poor service and/or punctuality. Please. What services can they withhold? Also, if they are late, not my problem. We have an organised pickup time. If their lateness is a factor which contributes to a delayed departure, then there’s a code for that in our admin report.
Anecdotally, as someone who flies long haul to Europe, NA, Aus/NZ ect three times a month, I can safely say that the ground transport product we receive in the US is the worst by a country mile. Clapped out prison-van busses with rattling windows, busted shocks, late arrivals and surly drivers all being fairly SOP.
I’m happy to tip the hotel van if they take us out to dinner or some such favour, and I tip restaurant workers well (despite not necessarily agreeing with the principle), but contracted van drivers to enable us to do our jobs?
In the lobby, most of the time a crew member has an envelope for drivers tips. If I have loose change, I’ll offload it in there. I’d far rather leave any extra $1 bills to the hotel wait-staff.
I fly with a crew of 16 most of the time. It’s a ridiculous notion that the driver should be tipped $16.
My job is to fly the plane. Their job is to drive the van.