[Istof]

Place a remote controlled gun next to that camera and you have a remote hunting system? (probably illegal in most jurisdictions though)

[lvs]

Uh, one that shoots at you? How are you going to get the tracking beacon onto your target?

[MichaelGG]

Setup system across from office entrance a month beforehand. Drop the tag into the target's coat at restaurant coat check. Trigger remote system based on proximity. Someone's probably already done this in a spy movie.

It'd be a much better idea to simply have a remote controlled system, using tech that's been around for decades. Though I suppose if you're truly paranoid, you might be worried about signals tracking. Maybe have it connected to the Internet and use thermite to wipe out the evidence after shooting.

[Istof]

couldn't you use the signal from the target's phone instead? ... cell, wifi or bluetooth.... whichever suits you