Years ago. Shooting a friend's wedding, medium format, interchangeable backs. Wedding coordinator gleefully shoves me into an elaborate dressing room. Bride sitting in front of mirror, almost, but not completely, in the buff. "Time for boudoir shots!"
This was NOT in the job description! We both have deer-in-the-headlights looks. Embarrassed, we both do our parts as best we can.
Film comes back -- blank. I'd left the dark slide in place, upside down, so it did not activate the release lock-out!
The good news? They were divorced within a couple of years, and she was glad he didn't have any revealing shots of her.