The few annual tournaments in Vintage typically do allow players to show up and register their deck is present, then put it away in a travel safe and play with proxies. That's for decks that can easily be worth 50-100k.
You can buy mid-quality proxies on Chinese sites for about $0.30/card that feel accurate and typically are only distinguishable from real ones on fairly close inspection.
The few annual tournaments in Vintage typically do allow players to show up and register their deck is present, then put it away in a travel safe and play with proxies. That's for decks that can easily be worth 50-100k.
You can buy mid-quality proxies on Chinese sites for about $0.30/card that feel accurate and typically are only distinguishable from real ones on fairly close inspection.