When I work on cars for others I inflate their tires for them. (only to sidewall max) Even if they brought it to me for a water pump.
I tell them what Ive done, and tell them why.
None have come back to tell me anything bad. (The car drives hard, i got no traction..you get it)
I have several now that come by on the weekends so we can do mods to the cars.
So maybe this belongs in "Success Stories" as well.
S.