Yep. :)
First I just wanna say, I appreciate the joke.
I can't speak for other countries but, in numerous states in the US, it is illegal to "incite fear" of bodily harm, even as a joke or prank. One common example is brake-checking other vehicles on the road. Another example could be placing "caution minefield" signs on your lawn to deter pet owners allowing their animals to poop on your lawn, etc.
I'm fond of the Phand.