My children attend a Gaelscoil and the school policy is to encourage the use of Irish by all visitors, including parents, in and around the school, particularly when the children are within earshot. However, it is understood that not everyone is fluent in Irish and all efforts are encouraged, in my own case I can respond to simple, straightforward questions, when it becomes too complicated the conversation can become bilingual!
With our Parent Association Meetings we usually attempt to use some irish, when welcoming everyone, some items are discussed in english and irish, and the cupla focal are thrown in when possible. Efforts are made not to exclude anyone. It can be daunting, but I would say make the effort to use some irish whenever you get the opportunity, like at these meetings, its worth it. You get more comfortable with the basics and its encouraging for your children to see and hear you take an interest....half the time I'm asking my 8 and 9 year old children how to say particular things before I call into the classroom to chat to the Muinteoir and they get a great kick out of teaching Mum how to speak Irish.
IMO, compromise may well be necessary on the part of the school in order to retain parents on the parents association. It can be hard enough after a while to keep a parents association running without additional barriers for volunteers i.e. language.