"As If": This was added to the FAQ (v.1.7, March 2020) and then amended (v.1.8, October 2020). You can read the October ruling on the ArkhamDB rules page here. (I'm adding a hyperlink rather than retyping the rules in case in future the ruling is changed or amended - at that point, the rules page will be updated and all ArkhamDB FAQ entries will link to the correct ruling.)

Q: Double, Double vs Pay Day. Can the of Double, Double be initiated despite the end of the turn [from Pay Day]? If the turn immediately ends, does this mean even if Pay Day is played again, no actions were performed and the second pay day will grant no resources? A: Technically, you can use Double, Double to play a card that ends your turn twice, even though it ends your turn. Ending your turn doesn’t mean that you can’t trigger effects, it just means that you can no longer take actions. Since the second playing of the card doesn’t cost an action in this case, you can go ahead and resolve it even though your turn has ended. HOWEVER, due to the specific text on Pay Day, doing so would essentially do nothing. It says that you gain 1 resource for each action you performed this turn. Since you are playing it outside of your turn, you would gain 0 resources from the second copy of Pay Day (since the first copy ended your turn.)

Q: Double, Double vs The Painted World. I imagine The Painted World cannot be played twice by Double, Double, since it's removed from the game, but can the copied event be played twice? A: You can absolutely use Double, Double to play The Painted World twice. Note that it says you play it “as if it were in your hand,” so each time you played it in this way, you could choose a different event beneath Sefina Rousseau. Keep in mind this may not work with some events (such as events that become attachments or go to a specific play area) as you only actually have one physical copy of The Painted World to move around.

Q: Can you use Double, Double on Scene of the Crime (as Tony)? Can you Double, Double with Evidence!? A: Yes, you can. You can use Double, Double on Scene of the Crime because it is still technically your first action (the second playing of the card does not cost an action). As for Evidence, it is a reaction to defeating an enemy, so as long as you are still in that same opportunity window (having just defeated the enemy), it is perfectly legal to use Double, Double to play it a second time. In this way, it’s no different from having two copies of Evidence in hand and playing both of them, one at a time.