Idea to snare attacking trroops

I would like to see on the next upgrade a new type of defence that can be purchased from the shop:

I would like to be able to lay a hidden trap that captures enemy troop(s) when they attack your village; you then get to keep that troop and use them for your army.

Level one snare can utilise a housing space of 1 (an archer or barb etc), Level two snare can utilise a housing space of 2 (2 archers/barbs/gobs or a WB), Level three snare can utilise a housing space of 4 (4 archers/barbs/gobs or 2 WB or a wizard), Level four snare can utilise a housing space 8 (eg: 1 wizard, 2 barbs and a WB), Level 5 can utilise a housing space of 16 etc, etc.

To hold the prisoners; a Jail can be purchased to retain the troops and can be used/upgraded in the same fashion as the clan castle.

Let me know what you think or if you need more clarification.

Cheers
Lee