As it stands, you can check to see if the player has an item (object) when they enter a room. What about checking to see if they don't have it?

I believe you can say "not have" in an if/else statement.

"do action if player NOT has object"

[MOVED]
Thought developer forum was more suited for this.

if not got <Object> then set string <has_object; false> else set string <has_object; true>

Something like that