I'm making a quest where the Whistle (Harp of Ages in the quest) opens portals on certain screens (ones with the familiar stump-like tile found in OoA marking portals to the past/present). However, I know that having this item as the Whistle poses a problem: if you have a Triforce piece, you'll call a Whirlwind when you use the "Whistle" on a screen that DOESN'T have any whistle flags. Is it possible to disable those? If not, I think it should be a new screen flag (or quest rule, if you'd like).
Can you disable Whistle Warps?
The only way that I know of is to have whistle for stairs on every screen. So no. I don't think you can.
This would definitely make a good quest rule, and then have a toggle for it as a screen flag.
The only way I can think of that hasn't been mentioned is to NOT use Overworld dmap types. Since whirlwinds only appear on overworld Dmaps, if you can use caves or dungeons for the entire quest, you should be okay.
I agree that we should have a quest rule to toggle this. I'll mention it in the beta 11 suggestions thread, if it hasn't already been added.