Do you have an air conditioner? It will dry out the air.
Hi, take the flags out and off the cake, place on a cake board and put in front of a fan of any size. Just somewhere cool. My back bedroom is cooler than any room in my home. I use it for this purpose when i need to also. Also put the fan in there and let it circulate.
Write a letter to Hera the God of air. If she doesn't reply consider shifting.
hahaha! OK, thanks, ladies. The fan helped a bit. I took the softest flags (red) and sort of attached them by the tips to to the poles of other flags with a fondant/RI patch. The client was happy, so all good!