With the things I have seen people do around kids and dogs, and those people truly believing their actions are sensible or even safe when they're the exact opposite...
And the general dog owning publics inability to understand their own dogs, particularly with the rise in popularity in aversive training that produces dogs that are highly likely to react without warning and far more likely to react towards strangers/children
I wouldn't let a kid of mine (if I had one) go to a home with a dog unless I knew how those people handled, trained, raised and kept that dog inside out and back to front. .
There is a saying in dog training circles... 'management fails'.
At some point, management always fails.
However if you're managing on multiple levels - ie:
- you don't have unfamiliar kids in the house
- your dog is crated if strangers are in the house
- your dog has two closed doors between them and your children in the house if you're not directly supervising (ie kitchen door and crate door; kitchen door and back door)
- your dog has been well socialised and habituated, is not nervous or fearful or easily excited...
- your dog does NOT associate cues to go to their bed, get off, move over there, come with me/leave the room etc with punishment/fear/pain
Then when one of those elements of management fail, when someone opens a door, opens a crate, invites a kid in, asks the dog to move... you have very little chance of things going terminally wrong.
People will say 'yes, I'll crate the dog/the dog will be in another room with the door shut' etc... but the reality is, they relax, they think it will be fine... they haven't got set rules their own children understand and so the kids will open doors, let the dog out etc...
That is how children die. At least one of the historic child deaths was as a result of children (left unsupervised) who went outside to see the dog tethered in the garden. The dog recently bought from a pub, to be kept as a guard dog, who was known and sold as not child friendly, who they had been told not to go outside with, not to approach.
Another was when the person caring for the child, who knew the dog had a recent bite history on another child, allowed the dog into the house whilst the dog was terrified of fireworks, and had him sat with the child he subsequently killed.
Her parents for some inexplicable reason, trusted this relative to do as she said and not let the dog in.
I'd tell the parents you don't do playdates in the homes of people who have dogs you do not know well. That will do. You don't need to go into HOW well you'd need to know the dog.