...But if they're truly indistinguishable from the real thing then I'm having a hard time seeing damages done to players in the tournament.
It affects the game when I am honest and my opponent is not. If I play in a non-proxy event, or a limited proxy event, and can afford time walk, so I play an underpowered deck proxying my FoWs and Drains and library and sapphire (hitting my 10 proxy limit) with time walk and stony silences...but my opponent has 4x workshop, ALL the artifact acceleration, and anything else insanely pricey for the bargain price of $50 for his entire deck, not needing any proxies...then I am at a severe disadvantage. If I have to compromise what I can play out of sheer honesty...if we play an identical deck, yet my opponent can "afford" imperial seal and bobs, while I have to settle for spoils of the vault and 4x night's whisper...then I am at a sever disadvantage.
Not everyone is okay with buying fakes...and it makes being a person of moral integrity disadventageous when a cheater can play superior decks for the cost of my single bayou.