The delay isn't really cancelled--you have to have a "Cancel delayed actions" action somewhere to cancel anything with the "Cancel?" flag set. Bruce explains how that works in this post: [Released] Rule 4.0 - #62 by bravenel
Your rule will mostly work because, as stated above, you're testing whether it's still open after the delay. This creates almost the same result (except possibly more scheduled jobs that will just do nothing when they're run instead of getting un-scheduled when they are known to no longer be needed--probably not a problem), but I see one important difference. Suppose you do the following:
- Time 0:00 - open door (triggers rule)
- Close door (does nothing)
- Time 1:29 - open door (triggers rule again)
- Wait at least one second, then close door
In this case, it seems to me that between steps 3 and 4, you'll get the notification from the first triggering of the rule because at time 1:30, the IF in that rule will evaluate to true. The example from @bjcowles above that uses a "Cancel delayed actions" when the door closes fixes this problem by truly un-scheduling the execution (at step 2 in my example sequence) instead of just testing the state when it it scheduled to be run again.
