My 1st job out of the army was driving an airport limo. Fancy name for a cab.
I took a fare to the Hilton.
After being paid I checked the back as was my custom for anything left there. A large string tied manilla envelope was on the floor.

Not sure why I opened it but I did. Strapped $10,000 in $100 bills in it.

I hustled to the check in desk and found the guy. Gave it to him. He said "Thanks."

I never expected a tip. Actually I felt bad because I opened it.