[gigaflop]

Organized Play official events require authentic cards, but nobody is stopping people from using a printer for kitchen-table style games.

Personally, having used printed paper inserted over top of a real card, I'd rather stick with real cards. Otherwise, I'd just go digital in this day and age.

[doctrgiggles]

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.

[FanaHOVA]

That is not true. Try playing a $0.30 Underground Sea at Eternal Weekend and see how many rounds it takes before you get caught. Old cards have specific hues, imperfections, etc, that are not replicable in modern proxies. I have some Legacy proxies for local events that are proxy-friendly, and literally the first game I played someone noticed as soon as I put the card down that it was fake because it was printed way too well.

[tedunangst]

Are judges at tournaments pulling out loupes and inspecting cards?

[__loam]

Not really but the official line is you can't use proxies. Practically the only reason a judge would have to inspect your deck is if they suspected you were cheating by registering an incorrect list or pre-sideboarding or something, but most judges aren't going to care about proxies.