The Headroom prank interrupted TV people (presumably) wanted to watch, made broadcast engineers scramble, and may have even gotten a few woken up in the middle of the night. I won't even speculate as to what kind of pains-in-the-ass it almost certainly caused throughout the network and at the FCC going forward.
You really cannot see the asshole quotient here?
Pranks should be between friends, not unsuspecting strangers.