Would this bother you?

Is this strange or am I being odd? My MIL is watching my son on Wednesday and she usually does once a week. They normally just go to the park near where we live and get some ice cream and go for a little walk if they have time.

This week, my FIL asks me if they can use our car seat. I say yes and I ask them where they are going. He said to the zoo. I just tilted my head, like, oh cool. And he realized I didn’t know so he asked if my MIL ever communicated that with me and if she asked if that was okay. My husband shakes his head no. So my FIL asks if that’s okay and if it’ll be too much. I say it’s fine, which it is but I wish I had known.

Anyway, she acts like it’s normal to not tell the mother of her grandchild she’s taking him on a road trip to the zoo. And is laughing and joking and saying it was her idea and my SIL didn’t want to go that far. Whatever I guess.

Am I being overprotective or is that something grandmothers just do? I’m thinking of my own mother and she would never just say she’s taking my son somewhere without asking me if it was okay. My FIL seemed embarrassed that I wasn’t asked and my husband looked at me like, my marriage is over lol