Everyone arguing AGAINST FS in competitive play are just delusional.
FS's are extra special moves. They are EXTRA SPECIAL MOVES. They are unique for every character, and they avoidable(easily-watch yoshi vs pit..lvl 3 yoshi dodges all of pits FS), and must involve some sort of strategy to unleash them.
The way they are put into the board give ALL players a chance to break it. Strategy would be involved on how to open it.
The only time it could POSSIBLY be considered unfair is if it appears when a character is returning after being smashed. And even in this situation, I dont believe that any character would have enough time to break it open before the opponent could offer some sort of opposition.
Im sure that FS's would be considered tournament legal, but im also sure that just as people in this board are split, tournament goeres will also be split. I wouldnt be surprised if tournaments simply marked whether youd be using it or not on the advertisement.
"Tournament XXX, In Philly, @ BattleField/All Chars/FS's Allowed"
or
"Tournament XXX, In Philly, @ BattleField/All Chars/FS's Banned"
And Mic, im sure that this topic, and all the discussion around it invovles what happens following the initial tournaments, after people know the game mechanics better.