Wow...that's a weird way of doing things...

Though then again...my ways are always weird...

I end up with a switch for every treasure chest (Aiiee! Crazy ) and just have conditional branches for every treasure chest:

If Switch 001: Treasure chest TopLeft Map 1 is OFF

then you can open the treasure chest, which in turn switches the switch (001) on.

If it is ON, then you can't open the treasure chest...

----------

Which Rpg Maker you using boginziliac?