I’ve bought and sold houses a fair bit. I’m not wild about kids around 2-7 turning up. They need a lot of supervision, tend to be hard in their excitement to stop them bouncing on beds, touching stuff etc. and that’s not acceptable.
babes in arms not an issue
over 7s usually can do what they’re told and I’d expect the parents to reiterate as they come in, to their children, do not sit on anything, touch anything and stay with us in same room. If they don’t, I have said it myself politely.
I would have no issues at all, telling a parent to leave and stop the viewing if a child started wandering around, running, touching stuff and bouncing on stuff. I’d put it that one parent needs to take child out. And then switch over. As other have said a parent needs to focusing on the kids at all times to ensure they’re in control.
years ago (50 odd) my mum had a shorthand code for her 3 kids under 5 to come to order, and that was “put your hands in your pockets”. It’s hard to touch stuff if you’re not allowed to take your hands out of your pockets, or for that matter run around and jump on stuff. It was a good system, and an easy thing for her to say all the way through childhood when visiting people’s houses, shops, or stately homes etc and we knew that meant we could look, not touch, stay close and not wander off, no running, jumping etc.
The last house I sold the parents came seperately for first visits, with their Dad/FIL. Then they came togther the next day, during the day, when kid was in nursery. Sometime after I’d accepted their offer, they asked very nicely if it was ok to bring child as he was so excited, and I was happy for that. Child was well behaved- but then the visit was all about showing him around, so parents focus was on him and it was easy to ensure he was under supervision. I went out to garden with them to show child the newts and frogs in the Pond which he loved seeing.
So, yes kids should and can see property before completion- but preferably not on first viewings when parents are going to be distracted by looking around themselves. And especially not if 2-7 years until sale agreed.