exactly. plus, i buy the songs i use. if i were the artist, and the filmmaker purchased my song, i would have no problem with them doing free advertising for me.
on another note, for those of you that either haven't had your upload rights revoked or those of you who have them restored (if that happens), you can easily avoid getting in trouble with facebook by lowering/raising the pitch of your music. it's easy to do it by an amount that isn't very noticeable, and the thing facebook uses to scan the audio won't recognize the song.