Originally posted by Christian Gienger:
To me that sounds like an euphemism for stealing and theft is a serious issue.
While that's a true statement, it's important to distinguish between Unsporting Conduct - Theft of Tournament Materials, and a theft that happens to occur during or in connection with a tournament.
This example is the latter - what I'll call an “incidental theft”. Since this player is borrowing cards that they aren't returning, they're violating common decency (and most likely, local law?) - but even though those cards might be used in a tournament, it's not Tournament Materials. While the IPG is more specific in that definition than what we do for Regular REL, the concept still holds.
And here's the key part of the concept: some things are outside of a Judge's jurisdiction. We educate and enforce the rules of the game, not the rules of society.
As a store owner, you have the right to ban anyone you want from your store. I've heard players insist that Wizards requires you to let them play in your events - that's simply not true. Wizards wants to help you sell Magic cards, they don't want to tell you how to run your business. Even if you're hosting an RPTQ, and a player you banned is qualified to play in that RPTQ, you do not have to let them in your store.
As others have noted, you can't ignore your own triggers - but you might not know that, the first time. The Chalice situation you described might not be Cheating … the first time.
Mana weaving itself is not illegal, unless it's accomplished via multiple pile “shuffles” (not really shuffles). The rules only allow one pile shuffle per game, per player. Anything beyond that, we educate and instruct them not to repeat the action.
Failing to shuffle thoroughly and effectively after mana weaving is an infraction in the IPG, and an unwanted behavior at Regular REL. Mana weaving followed by a couple half-hearted insert shuffles, then present the deck? Educate the player - and, at Comp/Pro REL, Warning for Tournament Error - Insufficient Shuffling. It's important to assess and record that infraction, as a repeat that same day will result in an upgrade to Game Loss.
d:^D