Defensive "Catch"?

[Kryx]

Maybe I'm crazy, but I had an idea. What if any unit with an overland movement greater than 1(the whole unit, not just the comm) could have up to 3 "Catches." Ok, here is how it would work. On a turn, you can choose a new order called "Catch", and you get up to three catches, set in priority 1 to 3. What it does is, the unit does NOT move, and cannot move in this turn, unless it does a "catch." The way it would work is during the host phase the unit Queries all the catches in order, if a hostile unit moves into a catch it moves, and lower priority catches would be then ignored. Regardless of movement speed, the catching could only be done one province away. I personally think that this would make defending an empire's border 1000 times easier, and would be a good addition to the game. Visually, the catches could be green (instead of blue) arrows.