It's a brilliant/evil hack; it works by getting the expression source from the frame and building an AST from it. Lazyweb request: LINQ. (PyNQ?) ;)
Behaviour-regulating designs: the supermarket tile thing I posted the other day is one, but also websites that make it hard to leave, reduced visibility at roundabouts to improve safety... the list goes on.
Tiles -- Supermarkets used to have a trick placing slightly smaller tiles on the floor in the more expensive aisles of the shop. When a customer entered on of these aisles their trolley would click faster making them think they were travelling faster and thereby subconsciously slow down and spend more time in that aisle.
I've got an old phone in the garage somewhere; I'm tempted to buy a handsfree kit and make one of my own. It can't be that hard... (Famous last words.)