A mixture here, I don’t think there’s anything wrong with asking!
At the nurseries I worked in, when there was a special trip or visitor we had certain procedures we followed to make it fair.
So we sometimes had visitors ~ we had one of those companies that brings in some little animals for the children to see and hold, we had a puppet show company come in sometimes, and children’s entertainers sometimes towards special events. Now in this situation, if your child was in on that session all well and good. However if your child wasn’t in, we would invite them in for the event but a parent / guardian had to stay too. They only came for the event, not for example the whole morning. We tried very hard to spread the days out, some days were busier and we admittedly often aimed for those.
Trips were similar. A big trip, for example each year we took them somewhere Christmassy (local Christmas trails or a grotto or such) and likewise everyone was invited. We took responsibility for children booked in that day and other children were invited and had to have their parent, because we wouldn’t have the staff to match ratio otherwise. I don’t think we ever had a complaint about this, we certainly had some grandparents a couple of times who were the care givers that day. We only really did two what I call “big trips” a year (lasting half a day for example) - the Christmas one and a trip in the summer to a nature trail / a castle / farm / an outdoor adventure type place for example. These were the ones where everyone was invited. We never did a trip to a soft play I must say.
Smaller trips were more frequent and just done for the children in. I count these as trips where we went somewhere on foot, didn’t have lunch out or anything. These would be trips to a nearby woodland, the village shops, possibly to meet baby animals at a nearby farm down the road. These were on our standard permission form and we just took who was in. We tried to rotate the days for these so everyone got to go, and I think we did. I think the children who experienced much less were those who just did the afternoons because it was always much more practical and easier for us to do them in the morning, but yes, we make a big effort to change the day we did things to include everyone.
It’s definitely fair to say children missed events. Book Day was done on one day on,y, likewise Halloween. Easter stuff was done across a few days but the egg hunt was only on the day before Easter, (we were open all year round).
So I don’t think YABU - but they won’t answer on social media, go in for a chat, your child’s not been included, just ask the question, how are they planned? When is the next trip? Don’t go in all guns blazing but YANBU to expect your child to be allowed on trips like the others.