Yup, I've found a crack pipe once that fell out of a SW's pocket when she took her pants off, a hair clip, a lip chap stick, that didn't belong to my SO — you get the idea.
Back in the day when I used to pick up SW's, I would do a complete checkout of my car after.
Also, like the surgery team does with every surgical instrument, gauze pad, etc, that went into the operating room and is accounted for, every condom (unused or used including wrapper), bottle of V, burner, minutes card, etc that went into my car was accounted for after mongering.