@dlowan,
One of my Cunning Plans has just backfired.
I've taken to leaving bits of food around in almost impenetrable containers...like thick plastic.
The latest one is the remnants of their kitten food in its plastic sack. Theyve been working at that for days. Now it's nearly one am and viola is noisily working at it in my bedroom, where she just brought it from the living room.
Sometimes they steal stuff and work at getting it out of the container, then confidently bustle in with it together for me to open it for them....thus convicting themselves of criminal activity.