Sounds like you need to talk to them and address your concerns with them. And basically tell them that they will not be able to see your children unless they abide by your rules.
Originally Posted by lesley&grace
This is going to sound harsh, and I am sorry for that.
Repeat after me: "No."
If you mother has shown you repeatedly that she is unwilling to respect you as a parent, then you are pretty much accurately predict that she will continue to disrespect you as a parent and you need to say very firmly "No. No you cannot take my daughter anywhere because you are not willing to respect that there are things I do not want my children exposed to."
That said, I totally understand that you want your kids to have a relationship with their grandparents. In the right conditions, that relationship can be a beautiful thing. However, these do not sound like the right conditions. I would not be bringing my children to her home, and I certainly would not ever let her take my kids on her own. I would probably permit short, very supervised visits in my home, and she would be told to leave the moment she said or did anything I felt was inappropriate. If she has a problem with that, well...that's her problem.
Your #1 responsibility is to your children.