They are TOO strict. Okay I might be a little mad lol. DS came up to the bar at space mountain. I mean you could MAYBE fit a piece of paper in between his head and the bar. And they said no. He was soo upset.

:sad2
At
Disneyland's Star Tours, my son did get a piece of paper passed between head and bar, and was not allowed to ride. He was fully, bonafide, tall enough, but the CM freaked him out. The CM also was pushing down on his shoulder. DS thought the CM wanted him to bend down a bit, so he did. DH was there and didn't have the words to stop it from happening at the time.
It was a bummer, but ultimately, IMO, a child who can't respond to that by standing straight and tall and showing their true, tall-enough, height, is a child that probably isn't mature enough for a big ride. I know that's how we ultimately felt with DS. Went back a few months later, he knew how to stand, and stay standing, straight and tall, and it all went well.
Except that little kids with Star Tours tend to slide down, LOL.
I really wish Disney had a consistent way to do this. At Busch Gardens this summer they had a height check at the entrance and the kids were given colored wrist bands based on their height. It would be so much simpler to just do this once.
People say they did this once. And parents started slipping the bands off of one child and putting them on another.
Our trip 2 trips ago I was all excited that my son had reached 40 inches on our wall at home. Upon our trip to Disney he was no where near the 40 inch sticks. We must be terrible measurers or something.
There's also gravity working on the body throughout the day. And levels of hydration matter, because fluid in our bodies goes to the intervertebral discs which are puffier in the beginning of the day than at the end. We quite literally shrink through the day.
So you get a child who isn't eating normally, isn't drinking enough water, is sweating in the sun all day and running around, who is also not sleeping (resting on their back, letting gravity pull on them differently) properly....it's no surprise there are differences in being able to ride rides!
With my DS you couldn't see space at all. He was essentially touching the bar and the CM told me he had to pass the bar not just touch it. Maybe CMs are different but I got a strict one.
That IS a too strict CM, if he was fully pressed up against the stick. You probably could have made a comment to guest services about that (just like we could have spoken to "city hall" at Disneyland about the CM that was pushing down on DS).
I laid DS3 on he floor and pulled out the measuring tape...39.5 inches.
Laying on the floor is so different, as a couple people have said. This is very inaccurate for in-park purposes.