Bombs

I was considering the bomb related rules, and what do you guys think of requiring a mechanical component to any bomb? I'm not saying they all have to have, say, gears or whatever. I'm saying that you shouldn't just be able to go up to a target's car, stick a magnet on it, hope he doesn't check and call it a day.
Now, if you attached a magnet with a box to his car, and when he attempts to drive away a cord you attached to the ground pulls a pin out of the box or some such, now that works.
Another example, say for whatever reason you have access to a dude's house (Remember no breaking and entering). Just putting a note that says "BOMB" over his light switch is foolish. Hooking a noisy tape recorder or something to the outlet that is controlled by the light switch by the door, that's swell.

Another example, you can't just leave a box next to a guy's door, and so when he comes out he's "dead". A trip line (it'd better not actually trip him) or a motion detector, whatever. To avoid accusations of cheating or being unfair, might want to give the guy a bit of visibility on the bomb before the detonation step. I.E. the rope that is pulling the pin out of the bomb that is attached to the door allows the door to open at least 2 inches before HAPPY BIRTHDAY. Feel free to debate this.

Here's a couple of ideas from the book:
http://www.terminalpacketloss.com/images/Killer_Book_031.jpg

http://www.terminalpacketloss.com/images/Killer_Book_027.jpg