Then A disputes the claim a YouTube asks B if the they are sure its infringing on their copyright. B lies and says yes, then YouTube sides with B while A gets a copyright strike, 3 of which and you lose your channel.
Scammers are also extorting money from Youtubers using this feature of Youtube's claim process. See: ObbyRaidz
In case of conflict, YouTube shouldn't blindly side with the most powerful party as they're currently doing. Legally the fairest way would be an impartial judge, but in practice small players can't afford the legal representation for that.
Scammers are also extorting money from Youtubers using this feature of Youtube's claim process. See: ObbyRaidz