The Marketing slogan "This is all you need!" is slightly misleading. While I can see someone thinking "I don't need to carry cash during my trip!" I have a very hard time understanding why anyone would take that to mean they should walk around far away from home without any credit cards or photo ID (especially when they have an AP, with which they are asked to always carry a photo ID just in case).
My favorite such situation:
Steve: Hi, I'm sorry, our turnstile system is experiencing some technical problems. What kind of ticket do you have?
Guest: Annual Pass.
Steve: Ok, I just need to see some photo ID to verify use of the pass.
Guest: WHAT?! I have an Annual Pass!
Steve: Right, and because our computer system is not working right now, I'll need to see your AP and a photo ID.
Guest: I didn't bring my driver's license. They said I didn't need it.
Steve: Who said you didn't need it?
Guest: I'm staying at the All-Star and they told me all I needed was my room key.
Steve: I think that just meant if you wanted to use the room charge system or if you purchased admission on your room key.
Guest: Well I don't have a driver's license.
Steve: I'm sorry, but need to verify your identity. This is for your own security.
Guest: I DROVE all the way from (wherever) and now you tell me that you can't let me in!?
Steve: you drove here and you don't have your driver's license?
Guest: (silence)
Steve: Let me see if I can get someone to look up your birthdate with your ticket, and if it matches what you say, I can let you in.
Guest: I don't believe this!
Steve: Me niether...