According to this article, Casey said he was offered to be dropped off at one location. It does not say if he was offered a scooter in lieu of the cart. He was there to follow a couple of prospects but still technically a spectator, as any other college recruiters would be.
"I said, 'Let me ride this.' He apologized but said he couldn't. I said, 'I know I can use this cart, but if not, can you or someone take me around?' He said, 'We can take you to a point on the course and drop you. We can't cart you around.'"
http://www.usatoday.com/story/sports/golf/2013/06/25/casey-martin-golf-cart-oregon-us-golf-association/2458135/