After picking up my 3.5 yo DD from Daycare/ Preschool, I buckled her into her carseat and tightened the straps. She was angry because she didn't want to go home, etc. I turned back to check on her as when we came to a stop at a light down the road and she had completely loosened the straps.
DH and I are big into natural and logical consequences. We are stumped, obviously the natural consequence on unbuckling or loosening her belts is injury or death - not really practical. DH and I are struggling to figure out the logical consequence that will work.
She was able to say (after the fact) that she knew better. And she did it anyway.
We are open to any thoughts or suggestions.
DS is now in a high back booster. To truly be safe, (just as for an adult with their seatbelt), the child needs to sit properly - not lean about, flop way over sideways, etc. If he starts goofing around, I pull over as soon as I can. I just calmly tell him we cannot drive safely until he stays seated safely, and I wait. Pretty logical consequence. I have not had to do it often - he doesn't enjoy waiting by the side of the road much more than I do!
To clarify DD is still in a 5 point harness and I was able to tighten it back up.
We also live in an area where there aren't always safe places to pull over - and once I retighten her straps she is safe. So there is no ability to let her correct her own behavior.
And DD wouldn't care if we were stopped on the side of the road for an hour - unless she got hungry. We've tried a similar technique (we can't drive until you are in your seat & buckled) for times when she really fight getting into the seat - and then I have been stuck waiting in parking lots for 20 or more min. attempting to get her in her seat. those sort of delays are not always practical.
Maybe you could explain to her that the seat belt is for her protection. And that it makes you worried/sad/(whatever emotion she can understand) when she unbuckles because you're worried about her safety and wouldn't want anything to happen to her.
When my DS was that age I was able to explain that the policeman would pull us over and I would get a ticket if he wasn't buckled in tight. That was enough of a deterrant for him. However, for other misbehavior in the car I always threatened to pull the car over and make him sit on the sidewalk for a time out. I never had to actually do it, the threat was enough, but I would have followed through if necessary. Good luck!