I've done this mod.
I have read a lot of caution about it, principally for child safety. Nice idea, but it covers up the real problem - a responsible adult not being there to supervise them.
Please tell me when it's ok to let your children play unsupervised in any motor vehicle for whatever reason. And that those who do always place the parking brake on their manual trans vehicle? That children climbing on a dew covered roof are ok? Etc, etc.
I for one don't want small children hurt ever - but allowing them to play in my car is the first mistake in the chain. I don't allow it, period, for whatever reason.
I did the mod because my children understood not to play with the car to begin with.
Same for pets - no loungers.