For example: Going to a busy mall on a crowded Saturday afternoon... wearing a radiation suit with a geiger counter. And loudly proclaiming "Nothing is wrong, everything is fine, please continue as you were." Then randomly testing people with the geiger counter.
If I thought I could get away with it, I'd probably do it. I don't want to join Lex Luther behind the bars. It was a good idea until last fall though. :(