To not let them go

[glasshalf]

Hi
Trying not to be too recognisable if anyone read this so bear with me

So in-laws break up last year , relationship with MIL has been strained since a huge arguement 4 years ago. Since the split MIL has seen kids around 3x (not bio mum to DP)

Tonight she messaged and asks to take them for a day out . I initially say yes and ask for times. She stated she may not bring them back then some laughing emoji faces.
I immediately go into anxiety meltdown. She literally has nothing and yet makes little effort here, what if she doesn't bring them back what if she's not quite sound of mind since the split ?

So I've now said they can't go but my anxiety is through the roof over it. AIBU not to let them go and ask she sees them here for a few times before taking them alone?
I wouldn't ever stop them seeing her but I can't help worry she would do something to get back at FIL /me .

Thanks

Why doesn't she accompany you and the children on a day out, rather than take them on a day out without you

I suggested this , she's not keen , probably due to our strained relationship which is fine but I just feel I can't let them go alone (which in turn makes me feel a bit bonkers but least my kids are safe!)

Go with them. I never let my kids go with in laws alone. They never asked but that's a different story.