This looks more like an instructional sign than a prohibitory sign. A prohibitory sign would have a red circle around the picture with a red slash through the middle. It's like a visual description of a person-to-person urine transfer.
Does it mean you are urinating on the person in the wheelchair or the wheelchair-bound person is urinating on the the standing person ? Either way, that should only happen in the vacinity of the sign in the designated area !