No more AirCon for you...
I had a roommate who was a good guy but very careless. We shared utilities 50/50 so costs were shared. He had an in-window air conditioner and we lived in Southern California so it's often blazing hot.
Several times I came home to find him gone, bedroom door open, and air conditioner blazing. I would just go in and turn it off - no big deal. But then a few times I'd look in and he has the other windows open - and the air conditioner doing its best to cool the whole L.A. area ... And I'm paying for it. I mentioned it a few times (WHY even run AC when a window is open?!) but he never stopped.
Well...
I took out the power plug in the wall, and put clear Scotch tape around one of the prongs, then plugged it back in. No power connection - no AirCon. But it looks normal.
Later on, he came back and his AC is "dead". I said "oh, did you leave it running with the windows open again?" He had a lamp in the other socket so he knew there was power, he just couldn't use the AC anymore. Sorry...
Later when he moved it cleared the tape out of the outlet. Good as new.