[Jim S]

First off I don't think we as officials have the right to make this requirement to start with (it would lay with the governing body (local, state, etc. Whoever has the final say in your area). Second I would agree that it is most probably a violation of Feaderal ADA.
We had a head coach in a motorized chair for several years. Was never a problem. People used to love seeing him motor out to the To conferences out in the middle of the field.