Legal Question in Disability Law in California

If your question is can a vehicle with a handicapped marker driven by a handicapped person be parked in a private parking stall stating that it is only for use by customers of that store park there without going into that store, the answer is no. The exact same rules apply to handicapped drivers as all other drivers, except that they can park in handicapped spaces and do not have to pay public parking charges.

Ditto. Businesses provide handicap spaces for their customers only. Any other use would be a 'trespass' or violation. That handicap sticker does not confer any special privileges, only access to available handicap spaces.