If everything with bright lights, an electrical power source, and wiring was a "fake bomb" then..
HOLY CRAP, whats that strange box connected to your computer monitor? It must be a bomb! Run! Shut down the city!
If that box is attached beneath a bridge, has flashing lights and looks "home made" I hope you have the sense not to point at it and giggle and blow it off as a prank.
You and your "third dimension"
Grow up. If the idiots want to advertise their stupid, juvenile cartoon for their giggly fans, then don't place the "toys" under bridges. Buy a billboard.