We have those carts here too. I’ve had good and bad experiences with them which generally end up with her screaming bloody murder and me wishing I would have stayed home.
The problem is that she won’t sit with the strap on. I know that sounds impossible, I under stand that I’m the parent and she should do as I say but that’s a hard concept to get across to this child. If I strap her in she screams at the top of her lungs and thrashes in the seat fighting the straps. To the point of hurting herself, meanwhile people are looking at me like I should be doing something…what, I don’t know. I’m starting to think maybe slinging her would work but I’ve never slinged a child that old…guess it’s time to try.