Attendee

[Justin Bieber]

Following the standard pattern ([payee] = one who is paid), employee = one who is employed, [devotee] = one who is devoted), an attendee must be someone who is attended, i.e., the SPEAKER not the ATTENDERS in [the audience].

Used (with other similar patterns) by people too lazy to look up the correct word.

[Gregory]

A person who attends a conference or other gathering.