Heres my stance on it and apologies for my absence
A team is allowed to 4v4 or even play as a 4v5 if need be. I think it is sometimes hard to get all 5 players on so doing this is okay, however I think it is also okay for teams to play with 5 people if the other team only has 4 because the team with the full squad is ready to play and it would be unfair to them to bring one member off. I don't like it, but it should still be allowed.
The thing is though this late into the tournament roster changes shouldn't be happening let alone right before an important match. Because of this I think the match should be redone and if neither team can schedule the match properly then it will result in a tie.
As for some of the other teams, schedule your matches or your games will result in a tie/loss. I will be speaking to some of you about those matches.