Happens quite a lot, I imagine. It happened to us when I was engineering at CKLW Windsor. One morning the station went off the air when the pattern changed. My coworker who handled the transmitters told us that a raccon had gotten into one of the antenna huts during the night, and had crawled onto an inactive but still warm capacitor to sleep. When the pattern changed the capacitor went "live" and the racoon was fried instantly. Caused quite a mess, apparently. Sadly, it was a mother looking after several baby racoons, which my coworker had to shoo out of the hut with a broom.