Advice Needed - Babysitter set up by MIL

So backstory: I am SAHM with no family around and we rarely have had a babysitter (only after LO has gone to sleep, with references from other moms I know etc). I am a bit anal/protective/attached whatever you want to call it.

We are visiting with my in-laws and my MIL bday is tonight and she wants to go out to dinner and leave my 2 yr old with her cleaning lady. She says she’s fabulous/trustworthy etc. However, I don’t know this lady at all, but the restaurant is 3 minutes away so my husband thinks I’m crazy for saying I don’t think I want to go/have this babysitter.

This sort of problem has come up every time we visit them and it just always shocks me when she suggests babysitters and I’m too scared to say I don’t want to do that right away when she mentions it. She told me the info on Monday and I told my husband I wasn’t comfortable with it every day and to please tell her but he still hasn’t and we’ve fought most days about this since and now it’s the day of and I’m kind of panicked.

I just hate feeling bullied to leave my child with someone I don’t know. What to do?

I HATE causing conflict with my husbands family so this is really hard - for the most part everyone thinks I’m a pain (I think) but this is the first grandchild and I can’t just go with the flow anymore - I have to think about my son now.