Guests have the same access that users do in "Roblox" up to the point that they are unable to access any content on the website that is purchasable. This means that a guest cannot purchase add-on content for the game until she completes the registration process.
As of 2015, players of "Roblox" do not need to register to play the game. All guests are assigned random user IDs and a placeholder avatar, which allows access to the core gameplay. However, they can't access the in-game catalogue. Guests are also blocked from participating in the chat aspect of the game until they have made an account.