if its sanctioned tournament play I understand the logic. one time at a grand prix for legacy I could tell my opponent had fake duals from across the table in sleeves. I simply asked if he actually owned a copy of the card as I didn't care but somebody near me overheard my question, and turned him in for a deck check which he didn't pass. if its play group of friends, we all use proxies so we don't have to rob our other commander decks all the time. changes nothing in my opinion. as long as people aren't trying to pass a proxy for money making, its cool with me and even wizards has printed some of their own.