28 CFR Part 36 Nondiscrimination on the Basis of Disability by Public Accommodations and in Commercial Facilities NPRM (2008 Title III NPRM)

(8) Prevention of fraudulent purchase of accessible seating.  A public accommodation may not require proof of disability before selling a wheelchair space. 

(i) For the sale of single-event tickets, it is permissible to inquire whether the individual purchasing the wheelchair space uses a wheelchair. 

(ii) For season tickets, subscriptions or other multi-events, it is permissible to ask the individual to attest in writing that the wheelchair space is for an individual who utilizes a wheelchair.  A public accommodation may investigate the potential misuse of accessible seating where there is good cause to believe that such seating has been purchased fraudulently.