I'm not sure if the handle of their door is any higher than average, but they're generally 3 to 4 feet from the ground. I also don't know the height of the children, but I'm guessing at 4 and 6 years old, they'd potentially struggle with a handle that height. I'd imagine they might leave hand prints on the glass door if they used it.
Also in this pic, I just recently noticed what appears to be a smaller mattress laying between the two porches. Could be unrelated.
View attachment 586053Source of pic