Have tiles the ability to carry two flags at once. Having a high flag, which takes priority, and a low flag, which just gives other attributes to the tile. Here is one example of what one could do with this:
Have a invisible block they could push onto a push trigger, but can only be seen through the lens of truth. So we'd have the push flag as the high flag since it takes priority and we don't want the block suddenly appearing when we move it. And we want the lowflag to be a secret tile image of the block itself as a additional property of the tile so when viewed through the lens of truth, the players sees that they are indeed, pushing a block.
True, it'll be a change in interface when using flags in ZC. But I'm sure others can find more uses for the ability to use two flags for one tile space.