As a former fireman I'll re-iterate what Hanydman said, this would be an accident waiting to happen from a fire safety standpoint, especially if you're talking about foam egg crates instead of the cardboard/fibre kind. Doubts? Take several out to the driveway (or other safe area) and fact check us on the flammability issue.
+1. This is how the Station Night Club fire started in Warwick, RI. (well that and the pyrotechnics inside the club.) The entire wall behind the bands was covered in the stuff.