Aibu to find this "friendship" a bit odd?

[Rainbowunicorn73]

I have a 4 year old boy and my next door neighbour has a 5 year old girl. At the moment both children are in the garden a lot of the time. They get on really well but basically only have a friendship based on shouting through holes in the face or jumping on the trampoline at the same time and having a conversation when they can see each other over the fence (7 foot fence)
Several times when they're doing this I've tried to invite the girl round to play and so has my little boy.
We knock on the front door or shout invites through the fence but they always pretend not to notice, forget, don't hear the invite etc etc.
We went to the girl's birthday party this year and they played well (he was the only other child there) all went well and he behaved himself.
The parents are friendly when we meet on the shared driveway.
What do you think, I don't want to bombard them with unwelcome invites, we do have plenty of friends but it just seems to odd the two of them calling through the fence when they could be playing together properly.
What do you think?

YABU

The NDN probably have enough going on (especially over the holidays) and don't want to be pressured into coming out to play all the time!

Its also unfair to say the kid doesn't seem to have any friends - they probably have days out/playdates with their school friends but as its not at home you're not seeing it.

We have days out on weekends with friends but by the time we've got home and DC are tired and ready for their tea we don't really want knocking on doors to come out to play!!!

Um.... Thanks for the comment Pretty, I've taken what everybody said on board and won't invite him round again unless it's a mutual thing.

I didn't say or imply that she doesn't have any friends??? I have no idea whether she does or not.

The only thing I did say was that my boy was the only child at her party but that could have been for any number of reasons (we've only invited one child out for his birthday this year because of finances)

I only pointed out about the party to explain that the one time they were actually together they played really well and enjoyed each other's company.