I was wondering how a thread about toddlers taking their shoes off in the car could get so many responses! But now I get it.
I was going to say that your options are to get harder to remove shoes, put her shoes on when you get somewhere instead of before she goes in the car, or just deal the best you can with her shoes off and see if things improve. LOL. I don't consider dealing with it to be a punishment, unless you're browbeating her over it or approaching it in a shaming way or something. Sometimes putting her in a cart is just going to be easier than putting shoes on. One of mine was a shoe chucker and it gets crazy if you're on an errand with like 5 stops. It ends up taking a ton more time if you're searching for shoes and socks and then putting them on over and over. I finally just started carrying mine (I was not pregnant) and putting her in the cart when she did it, not intended as punishment but simply to save time and my sanity. And yeah she got tired of that and started keeping her shoes on. She wanted to be a big girl and do everything All By Her Self. (Two words intentional - that's how she said it.) Luckily this was in the summer as I live in a cold climate. I would have had to plan errands for when she could stay home with her dad otherwise I think, and she wouldn't have liked that either. They aren't going to be happy all the time. Life happens and sometimes you just have to deal with things the best you can.
Anyway, I'm glad everything is going well.