I Did that to my son's friend last year, so funny... when I told him I lost the key he said "cool that's ok, I kinda like it", so... found key and demanded my lock back.... yup, complete prank "FAIL".
Oh yep. I'm carrying a locked padlock everytime I am going to the university from now on.
used toughened steel padlock and spray paint it bright pink, then upload the video of them trying to cut it off with an angle grinder or a dremel cuz a hack saw just wont do it.