On Hide and Seek when it is a cash event it wont give out cash when you win just the hat.
You just obtain the hat the EC one is fine but i have experienced this on all Hide and Seek cash event i have played please fix .
You get money after you've collected all the hats.
How much money do you receive, i know there's already 20 hats
I haven't bothered collecting all the new hats yet but I'd say it's safe to assume it works just like the other money bot events and the amount of money is based off how many people joined (pretty sure that's how it works).