We had similar-sized events at about the same time. I provided some of the network cabling for our events, and we still have loads of coax ethernet cables, t-pieces, and terminators, all with yellow sleeves or painted yellow to make them stand out as "official stuff".

I remember one event over a long weekend in a sport and event hall, where a mis-configured power line provided 400 instead of 230V and killed a load of power supplies. Or the lines at the coffee maker: There was a long bench, and everyone queued their personal mug on that bench when coffee was out and/or in the process of being made. In a coffee machine that took one pack (500g) of ground coffee per run.