If you were a Muggle parent, wouldn't you be concerned that you literally never get to visit your kid's school? I mean, you'd had them all prepped to go to the local good Ofsted rated comp, whose catchment area you had carefully researched before moving in year 4. You'd been to two open evenings, and gone on a separate day visit, and then at some point in Year 6, a weirdo with an owl turns up and tells you your child is magic and is going to a boarding school you've never heard of in the wilds of Scotland...
Your requests to visit are refused, there don't seem to be any open days, parents evenings or speech days to attend. You don't even get asked to come when your little darling is lying petrified in the San....
All seems very unfair given that certain parents seem to be there every other week (looking at you Malfoy senior.)