Just guessing, but it seems like you could duct tape a phone with a data plan and have it email you it's gps coordinates every 15 min under 10,000ft and every 5 min under 500 ft, or whatever is reasonable. I bet 80% of them land within reach of one of those extendable tree limb cutters, let them drop to the ground and drive off; and the other 20% are merely cost of doing business.