MIL (shocker) causing riffs again.
I needed MIL to watch DD on Saturday so that DH and I could go shop for a new car. She was fine with it. When we returned to get DD MIL tells us that she took her over to SIL and BIL house for a visit. I was extremely pissed.
I've asked her before not to do this and that if she plans on taking her places to just let me know. I think it's in my right to know where she is taking my child especially if I was under the assumption that they were laying low. Am I wrong.
Background

D had been running a fever 103/104. I had to take her to the Dr. on Thursday because she was cranky and just not herself. There has been something going around with 3 out of 5 of the kids at her daycare but it caused one child to be rushed to the hospital. DD was on the mend but still a bit cranky on Sat. MIL KNEW ALL OF THIS!
She doesn't seem to get that I don't want DD around BIL, SIL and their son. Why does she keep forcing them together?
How can I say politely I don't want my child around them or their kid?