If it is not an official FFG event you do not have to allow IDs
This is true, but if you are going to change the rules I would make sure the group is well informed prior to the event. If people show up expecting a certain experience and end up with something different they may get irritated. Small rule changes like no IDs might not be a big deal, but we had an event where we banned certain cards just for a meta shakeup. We talked about it adnauseam to make sure everyone knew about it.