addon modules in missions - do players need to download them separate?

[Mayhem McAwesome 10]

i was wondering...

there are a bunch of addon modules out there... some seem really interesting, but i came into a rather relevant matter about their use...

if i include a downloaded module into a mission i made, then play that mission on an MP server from which joining players download it automatically, will they get the "this mission cannot be played... - ...depends on downloadable content..." message?

or do addon modules get PBO'ed along with the mission?