If you're talking about the electric recreational scooters, yes, they are allowed on the sidewalks at FW, but not on the streets, according to their website.
I still don't understand why they allow these and not skateboards and ripsticks. We saw a girl ride her electric scooter last week right out of the loop across the crosswalk to the trading post without even looking up. She came INCHES from being hit by a car.