Are sideboard guides (external notes) allowed at Skirmishes, and when can they be referenced?

Ruling: Yes, sideboard guides and other external notes are allowed at Skirmishes. You can refer to them between games during a match, but not during a game itself.

Sequence:

• Between games (during sideboarding): You may refer to pre-prepared notes from outside the game
• During a game: Your note sheet must be blank at the start, and you can only refer to notes taken during that specific game

Nuances:

• You can look at pre-prepared notes between games within a match (BO3), not just between matches
• The rule applies to notes from before the match being referenced between games