Actually, they come pick you up from your hotel and take you to their main bus stop, gather everyone up and then leave. We looked into using them on when we were flying out at christmas time. We were going to do the opposite leave from Anaheim, and come back. Howard was working till 9pm and we had a 1am flight out of LAX. Coming home, we were landing at LAX at 11pm the night before Xmas eve. We thought about having my parents drop us off at the bus stop and drop my car off there earlier in the day and we'd drive home. We decided against it mainly because I was worried we'd miss the bus when Howard got off and we would have to wait around for an hour. I was also worried that if our plane landed late and we didn't get our bags in time we'd be stranded at LAX in the middle of the night.
My parents decided they'd transport us, then my sister got them tickets to see a concert in LA, so when it was over they headed to the airport and got there right about the time we landed.