Rene, my 18 month old grandson can escape from any carseat. A short trip to the grocery store usually requires I pull over a good half dozen times and return him (thrashing) to his seat.
I've tried several designs, including the five-point safety harness which was fitted to him by someone who runs workshops on car seat safety. He was out of that one within three minutes of purchasing the thing.
I have tried distracting him with books, toys, and treats. I have tried threatening him, punishing him (with everything short of a cattle prod). I'd have duct-taped him into the seat by now, but the police department told me it isn't allowed. Considered abuse and makes it too difficult to get a child out of the car quickly if needed.
I have spent beaucoup bucks at Home Depot and Jo Ann's Fabrics on "stuff" to fashion belts and harnesses which I hoped would keep the little guy seated and allow the car seat to do its job. "Teeny Houdini" could free himself within minutes from every one. BUT I finally came up with something that works.
Have you ever seen hospital chest/vest restraints? They are a vest that crosses the chest diagnally from chest to waist, with straps or ties at the waist that can then be tied to hold the wearer in a seat.
I altered a size 2 vest (sewing) pattern so that the front continued to the side waist (instead of meeting at the center waist as usual) and added ties with an adjustable clip so I could tighten the ties as much as needed. I also put belt loops at the side waist to thread the ties through. (Hope this explanation makes sense.)
It takes an extra minute to slip the vest over his head and then tie it over the armrests of his seat, but he can't wiggle out of it, and he has to stay seated--and therefore, safe.
He protested the first time he discovered he couldn't escape, but then adjusted to wearing it without too much protest. After a few wearings, we were able to discontinue using it!!! He must have figured it was easier to just stay seated.
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But I'm afraid she's confused about her new seat. The seat you describe does not exist - at least not in the U.S. or Canada. There is no carseat that goes up to 65 lb harnessed and converts to a booster. The seats that go up to 65 lb are only made by Britax at this point, and run around $200. They are for harnessed use only and cannot be used as boosters later. There are plenty of harnessed seats that convert to booster use, and they are available in a wide range of prices, but none of them can be used with the harness above 40 lb. They have weight limits of 80 or 100 lb, but that's for booster use - they all have to be converted to booster use after 40 lb. Perhaps your SIL saw both types of seats when she was shopping and got them mixed up in her head?
