UX: Don't show "Participate as" if one profile
Several new users were confused by the button "I participate" -> "as" my profile".
When they arrived on an event, they would authenticate themselves, and when they clicked on "I participate", they thought they were registered. But some of them didn't choose "as" their account when they only had a profile.
If there is only one profile, there is no need to ask which profile to use. It is the user's profile, by default.
The question should not be asked if there is only one choice. This is confusing for users who think they are registered after clicking on "I'm participating".