MTR 2.7:

"Players are required to register their decks and sideboards (if applicable) in Competitive and Professional REL
tournaments. The Head Judge may require registration in Regular REL tournaments.

Registered decklists record the original composition of each deck and sideboard (if applicable). Once your
decklist has been accepted by a Tournament Official it may not be altered."

Can I act on the assumption that the bold text also applies to decklists submitted at Regular REL? This means: If the decklist doesn't match the actual deck, I (being the judge) have to fix the deck instead of fixing the decklist, even if the deck is legal?

Edited Jasper König (May 4, 2013 11:00:33 PM)

Regular REL events really shouldn't use decklists, but if they do, I would apply the MIPG principle of correcting the decklist rather than the deck (even though Regular doesn't use MIPG).

The bold text does also apply to Regular, if you choose to use decklists. However, at Competitive+ REL, if we find a mismatch between deck and decklist, we correct the decklist to match the deck. Why? We want players to play the deck they want, and the deck they want to play is usually the one they have in their hands, not the one they wrote down. The one they wrote down may have mistakes, or the player may have changed sideboard cards last minute, or a number of other reasons.

I think we can/should apply that philosophy at Regular.

So the bold text is solely aimed at the players, so the judges are allowed to alter the decklist to fix any mismatch between the deck and the decklist at Regular REL? We have a large tournament series at Regular REL that uses decklists, and that's the way I handled this kind of problems, but when I read the marked text, I was a little bit confused.

So the recommendation is to use the remedy that's given in the MIPG? Thanks!

Edited Jasper König (May 4, 2013 11:20:40 PM)

The recommendation is to run events at Competitive if they're going to use decklists :)

I actually know of one store which requires decklists for their FNMs as a way to verify that newer players have built a deck which complies with the format and to help educate those that have no idea what the format legality is prior to them showing up for the event and feeling bad about it. This shop is relatively new to Magic and their player base is mostly new people to the game, aside from this type of situation I'd be hesitant to recommend decklists at regular.

Bryan: That is a good idea to help new players!

I think an even better customer service route would be to have the judge look over all new player's decks prior to the start of the event. Filling out decklists is a tedious process– I certainly don't enjoy paperwork. If we can make events more about fun, it can often improve the event sizes.

I've also seen (I haven't done it myself) rel regular events use decklists because a known sleazy/repeat-cheating player walks in the door. Investigation skills may help to deal with that.

Edited William Anderson (July 16, 2013 03:36:20 PM)

When you want to use decklist in Regular REL, I recommend to think about the reason why you want to do so.

*If you want to do so because prize is high, I recommend you run that tournament in Comp REL.
*If you want to top-finisher decklist, I recommend you ask only top-finishers to write their decklist, which will be exchange for their prize.
*As William said, you may want to use list because of cheater information. You could find and catch them even without decklist. Please be careful of his play, which is more important.

*In case you use decklist in Regular and find error in decklist, I recommend you fix DECKLIST, not their deck. In my experience 99% of deck/decklist mismatch is small error in writing their list. “Please fix your deck” is not player-friendly solution.