GPS hidden in a steel tube .... no signal, useless. Aerial exposed, fixed in a second with a hammer. if 'every trap' is fitted with a tracker it becomes a simple process to disable the device as you nick it. How do you service it? How does it send out a position / alarm signal? needs a transmit aerial, can be cut off with a pair of side cutters. Quite apart from the fact that a significant number of grounds I have visited have little or no GSM / mobile coverage.
The mechanics and electrics of a trap are simple. encoded controls will simply be unscrewed and replaced with simple 'old' style controls. If not demountable is a trap scrap once the controls stop working? if a code gets lost or erased how do you re-program it, who has the tools and authority? Sound like the control codes of a car radio much?
Remember that a trap lives outside in the rain and cold. batteries go flat and certainly can't be relied on. Even a simple system would require a battery backup that, beyond 2 or three days of monitoring, start to grow in cost quite rapidly.
I worked on tracking 40' containers on a worldwide basis years ago, there are some serious challenges in what appears to be a simple problem.