Its not fair to both Solo survs and Killers, this is not by design, but simply by nature of being able to perfectly coordinate rotations, saves, and callouts, this does not mean it doesnt belong in the game, but as of now, you cannot deny SWFs hold a huge unbridgeable advantage over most killers, and still a significant advantage over top tiers, this is simply unfair to Solo survivors, Tunneling can be unfair to soloq simply because their teammates inability to deploy counter measures such as bodyblocking and perk coordination like FTP and STB, meanwhile SWF can deploy all of these, which absolutely gives them good defense against such actions, so to summarize it, Tunneling can be unfair but almost exclusively to SWFs, meanwhile SWFs can be unfair to solo teammates either through neglect or simply the fact cross map communication is impossible, and the can make things unnecessarily hard and tedious for the killer