L.A.
Maybe your husband and his family are the types of people that under estimate the ability of children..
We would allow our daughter to try things way ahead of what was seen as "in the normal range". She always far exceeded the average child physically and intellectually.
She had her own fears and limits, we did not let her jump off of the roof of the house, but we did have a glass coffee table since the day she was born and we NEVER had one child who visited our house try to climb it or bump their heads on it..
Our daughter always wanted to go down the "big slide" on the playground. . She could swing outside of a "childs" swing at 18 months.. We let her fall we let her tumble we did not allow her to fall far enough to really injure herself, but she was amazing at figuring out her limits with just a small amount of guidance.
They have to experience some failures, so that they are not afraid to fail sometimes.. We as parents use to model reactions to our own failures so she could see there was nothing wrong with that. I am notoriously clumsy.. So is my mom, so my own tripping, falling stumbling, falling were a pretty regular occurrence with a lot of " Uh Oh, mom fell again". She new that is it was normal for people even grown ups to get boo, boos..
It is just a different mind set to allow kids to really explore.. Some people just really do not want their kids to experience pain, discomfort or failure, but this is a safe time for kids to learn it is part of life and we survive and move along.
I know all children are different, but I also knew our child was adventurous and curious and I was not going to allow that to be stymied in any way.