On the topic of it falling over....
This is no different than any child's nylon-style play tent. If they play rough with it, it will fall over. My son had many of these style tents (not nearly as large) and he quickly learned not to tip it over.
When used outside, it has anchor loops at the corners that you can use to hold it to the ground. You can pick up tent stakes at a hardware or sport store.
Here's a picture of the loops:
I also don't see how it can fall down without pulling the walls in as though you were getting ready to compress it down for storage.
And I'm proud to say that two of us that both admit to being challenged with twist sunshades managed to get it up and put away.