We went to a family event yesterday with a religious element. There were children there - maybe 10% of the total headcount.
They varied widely in behaviour, from unnoticed to disruptive. It was charming to see them playing like children; less charming to hear some kind of electronic game beeping and whistling through the address and the prayers
with parents looking on indulgently.
The hosts had done absolutely everything possible to make it child-friendly (toys, drawing, stickers, pick&mix table, uncomplicated food, etc) but they were not well repaid by all of their guests. They weren't asking for hours of silence, only maybe ten minutes of keeping it down. And some people didn't even try to enforce that.
We married young, with no close family babies, so we could choose a grownup party venue and exclude children - we didn't even know any of the children associated with more distant relatives, colleagues, etc. And I'm still glad that's what we did.
We're having an anniversary party this summer and now nearly everyone has children, so we are planning a totally child-friendly afternoon event so they can all come.