Looks like Trion is trying to make it even easier for new players to try Rift. If the streaming client to almost instantly be able to login after downloading it’s small patcher wasn’t enough – it appears as though Trion is allowing users to play as a guest, without an account, up to level 9 (with certain trade/chat/etc restrictions of course). The idea behind it is to easily give users a way to try the game out to see if it suits them.
Pithos detailed it on the forums:
Here’s some facts you might like to know about “Play as Guest”, as someone who already has a Rift account.
Play as Guest generates a unique guest account for the computer you’re playing from. Every time you log in to Rift as a guest from that computer, you’re accessing that same guest account, *unless* you Register that account in game, at which point it’s a real fully functional account. At this point, if you play as guest again, it will create a brand new guest account.