A question about reliable context triggering

There is a question that continues to haunt me … how do I ensure that I “trigger” the correct behaviour when I am in a certain context? For my key contexts this is usually not an issue. My @work and @home contexts are properly geofenced and my iOS devices alert me through OmniFocus when I get near. No, what I really am getting at is those contexts where triggering the context is dependent on a number of factors, including my availability.

Let me give a concrete example … I have this @calls_work context, in which I put the calls I need to do whenever I have some down time between activities at work. I have often found myself going through my task list at the end of the day just to happen upon this list, realizing I never got triggered to “do” these calls.

I asked the GTD LinkedIn group for ideas and assistance. If you care to join the discussion, please feel free to do so here. It does however require a LinkedIn account.