If someone is using a motorized chair, wheelchair, Segway on a trail the reason may be physical lack of mobiliy. ADA does not define a mobility aide specifically......just a device that allows the disabled to enjoy what the rest of us take for granted, makes access to areas and events possible, and assists in maintaining the ability for self care etc.
Why would someone have an issue with it? Advances in technology (lithium batteries, self balancing machines, lifts for pools) have improved the quality of life for many injured veterans, children born with genetic problems, others with physical afflictions.

Excellent post. :coolsmiley:

Not asking if it is an issue with anyone. Asking where are they legally able to use one.

I believe the ADA law states if one can walk there one has the right to use a mobility aide there. So yes, if one can legally walk on the paths the jazzy is also allowed.