nablaWhoever comes from lower bracket has lost a match already because they were in lower bracket. If the upper bracket winner loses a bo3 in grands they would have the same playoffs record as the other team, but would arbitrarily be 2nd instead of playing again to settle the score.
yea, the actual most fair option on paper is to have to have (potential) double grand finals, like they do in melee. this doesn't make logistical sense for games where a match can take hours, so map disad is a compromise that's actually generally* more biased to the lower bracket team
https://liquipedia.net/smash/Smash_Summit/11
mango won both GF games and won the event, but would have lost under the map disad ruleset, since zain went 2-0 up in the first match