Maestro for big 4.5 year old and MIL issues

I already have 3 cars outfitted with seats for my kids (me, DH and my mom). Now MIL wants seats put in her car too. My mom lives in town and keeps or transports them on a regular basis, so it makes sense for her to have seats. MIL lives about about 45 minutes away. We see her fairly often. We've been just moving seats to her vehicle when she wants to take them home with her for the night (once every couple months). MIL is also constantly transporting her other grandkids, nieces and nephews. Most of these kids should still be in boosters or ride in the front seat when they shouldn't anyway .... but that's another story and I've tried to convince her otherwise. If I install 2 car seats and insist she leave them there, then the likelyhood of these other kids riding in the front seat are greater. She picks a 5 yr old and 7 yr old up from school a couple days a week, and an 11 and 12 year old stay with her on the weekends... all of these kids just ride in a seatbelt, and swap out riding in the front.

She's buying our 2006 Jeep Cherokee with the terrible headrests that don't move, so car seat options are limited. (That's why we're getting rid of it!) She currently drives a van, which makes much more sense with all the kids she drives around. I have a spare Scenera for my 2.5 year old, so I'm hoping that one will work in the Jeep. My 4.5 year old is in a Nautilus in the other vehicles, and I know it works in the Jeep. I hate to buy a 4th Nautilus. My 4.5 year old is tall and 43 lbs. Height-wise she's fine on the Maestro and has some growing room, I'm just concerned about the weight limit and if it's worth it to buy it for such a short time. If I only have 1 seat permanently installed in her vehicle and then I swap out the Nautilus when she takes them, then maybe one of the other kids will get to ride in the backseat more often. I think she's wanting to be more spontaneous and just let the my kids ride with her when she's here in town with us, or take them home with her more. I don't know if the Maestro will fit in the Jeep. But I could always trade it with one of the other Nautiluses we have though.

MIL was babysitting one day about 6 months ago and just put my kids in her backseat in seat belts and took off to the park (ages 4 and 2). The park was ONLY a short distance away, they weren't going very fast, etc. etc. My 4 year old told me about it when I got home. DH laid into her pretty good and she called and apologized later. She's not going to do that again.
She's currently got a broke foot (right foot) and is wearing one of those big boot things that goes up to her knee. So she's driving somehow with her left foot with her legs crossed.... and she wants to take our kids next week.
She's constantly on her cell phone in the car. I don't think she texts, but just the act of fumbling thru to dial a number is pretty much the same thing.

I guess I've always thought that by not giving her seats, we have more control over the kids and she can't just take them all the time. I already didn't really trust her before the park incident, and I know she apologized, but it's just hard to forget those type things. I know I've described her somewhat poorly here, but she really is a loving, fun grandma, and a great MIL. DH sees and understands most of these issues, but he wants us to get some seats for her.

Thoughts? Opinions?

Honestly sounds like you have many many reasons why you don't want her to transport your kids. Good or bad reasons, you mention them all because deep down you don't want her driving them. So if I were you, I wouldn't give her seats...simple as that. You have a great excuse because of the other kids she transports. The new vehicle will only seat 5 right? If so and you have 2 carseats in the back seat, the 2nd kid she picks up on the weekdays and weekends will be smooshed between 2 carseats.

Remind her that she only takes them on rare occasions and that it's no big deal to just transfer their own seats over to her car (even if it is)

If you are not comfortable with her transporting them, then don't let her. Hopefully it will wear off soon and she won't hold a grudge or get upset with you. And even if she does...your kids come first!

First off she shouldnt be driving, second, she most definatly wouldnt be driving my children with that boot. I wore one for 6 months, what she is doing is in no way safe.

I also would tell her she puts BOTH hands on the wheel and leaves the phone down while your kids are in the car. Car crashes are the leading cause of death for kids 1-14. PREVENTING a crash is the best way to keep your kids safe.

I would look into a Maestro, or see if you can find a GN on sale. I saw one on nobetterdeal.com last night for $108, I dont know if its still there.

Darn phone, hit send early.

I was going to say, and leave the new seat at your house for her jeep. I wouldnt be letting my kids in the car with her right now though, you have to think of their safety first.

Just to empathize and give mortal support...My in laws are lovely people and good to my kids but no waaaaay in hell they are transporting my kids. Both show poor judgement in transport decisions and are IMO bad drivers. Not gonna happen ever. Actually they are just not left alone with the kids ever...we do family visits. I have not discussed this explicitly with my husband because I make sure the situation doesn't come up.