I had a crew that came in a couple times a year to assist our, engine builds on the base. Every time the crew was there my lunches would come up missing.
During the fall session before they arrived, I told my friends not to touch my food, I was experimenting with fiber products and sometimes the results were unpleasant.
When the crew arrived for the assist, the first day no one touched my stuff.... the second day someone did...it went missing.
The third day I got called into the office, someone asked me if I had "sabotaged" my lunch. I said "no, I am experimenting with fiber products to keep my system 'regular'"
The boss then proceeded to tell me one of the assisting crew was taken to the emergency room and was now in recovery.....seems he could not stop emptying his bowels.
I told the boss....dang...guess I better ease up on the Fibercon then...I don't want that happening to me.
Couldn't do anything to me.... I had warned folks.... and the assisting crew member learned his lesson.
I would say put money in the open that has been "tainted" with something that would show up in a blacklight.....or maybe with some super hot tobacso type stuff that would burn fingers.
But be sure you don't handle it, and if someone visits, remove it or tell them what you have done to it.