Very cool prototype, but this is essentially the next Segway, except you sit on it and seems somewhat more portable.
I doubt it would be allowed. There doesn't seem to be a very easy way to stop at the drop of a dime or lock it on one spot for a duration. In a crowded situation, it could be dangerous. Disney doesn't allow Segways or roller shoes. It also doesn't permit ECVs in many of its queues and attractions. I also can't imagine something like this allowed on a parade route. Imagine trying to stay balanced to stay in one spot, but then you lean forward to see the next float and zoom you are off into the parade route.
Besides, the average tourist would screw things up and cause all sorts of accidents. People trying to ride with two passengers or with a baby. People trying to do tricks. People thinking they can go anywhere with it. I've seen people plow ECVs into curbs or completely just fall off of them for no apparent reason (seriously, I have). No offense, but the average human doesn't seem smart enough to use one of these safely and properly.