did you make any mention of the water you would drink at the event?
what about the use of their tables to place your equipment on?
did you stand on the floor? although minor, i imagine your walking might have weakened the structure of the building to a small degree?
do you know exactly how much it contributed?
perhaps you should hire an engineer to find out?
did you speak to anyone there not 100% necessary to your job? did that distract them temporarily from paying attention to the event?
i think your Halachic problems are just beginning.