I've either experienced consistent 1-second controller lag, where I'd hit the button and a second later my character would do it, or if the controller is great, consistent gameplay lag, where everything slows down a bit or skips like an awfully damaged CD.
Either way, it's impossible to play precisely and ruins a good deal of the strategy. I usually resort to slamming on moves I know will hit, which consists of forward smash! forward smash! forward smash! forward smash! with maybe a down smash for measure.
It might be, but honestly, who'll be stupid enough to find out? Its about as likely to happen in the middle of a battle as Roy's Flare Blade was in Melee.