Jackal- thanks- that gives me a bit of hope. I'm hoping maybe just someone else has the car out right now, and they'll look the next time it comes back. It's on the keyring after all.
And yeah... it'd go in a plain envelope with a stamp.
For some random unknown reason, Hertz's IT system sent me five (5!) emails all around 2am PST this morning, letting me know my item hadn't been found. Thanks, I guess.
I'm not gonna complain about the wait - the weather is nice and there's a second gym I can use in the meantime.