to say no to this visit?

[Myholidaywoes]

Our niece is visiting us at the weekend (Friday-Sunday) and mil informed us yesterday that our nephew (21) will come as well with his girlfriend (16), who we have never met. It is weird that communication has been via mil and we have been told, not asked, about the visit but that's another story.
Having family visit is a calculated risk I am willing to take but I am not comfortable with DN's girlfriend coming as she is still at school and therefore in contact with loads of other people - no school holidays at the moment where we live (non UK)
They will be coming from an area which is not badly affected by corona and our area is also not badly affected (yet) - both areas' 7 day average are about 25.
In pre-corona times I always said the more, the merrier but at the moment it just doesn't sit well with me. DH has no problem with it and thinks I am being unreasonable for not wanting DN's girlfriend to come as well. I would like to explain to DN why I don't think it is a good idea for his gf to come to stay and that is nothing personal.
Should I grin and bear it or put my foot down? There are no rules where we live on how many people can meet up but have been advised to reduce social contact.

I wouldn’t like a total stranger staying, DNs girlfriend or not. I would just make excuses and say it’s not suitable. The numbers are getting higher every day, it’s not worth the risk.

NO that would not be happening. 🌺

If people want to stay they should be asking!
It would be a no from me.

Just tell her that you are sticking to the arrangements with the niece and that the nephew will have to come another time- not while cases are so high in schools.

I think I'd be uncomfortable to be honest hosting a 21 year old with a 16 year old girlfriend. That is a big age gap for a 16 year old. Nothing to do with Corona!

It's odd that the gf would want to come and visit a stranger unless you live in a tourist place and its odd that you were told not asked.

I'd just reply and say you'll have to have the nephew and gf over another time as it will make social distancing tricky having everyone e there at once

I'd just say no , to all of them .

Absolutely bloody not!!!! Cheeky gets.

Even besides covid I wouldn't want some random 16 year old child coming to stay in my house with her adult boyfriend!

I'd tell my mil "Actually it's can nephew and girlfriend come to stay not they are, you ask you don't tell me who is staying in my home. Anyway the answer is no, nephew can but girlfriend can't. I'm not hosting strangers and certainly not children"