LoJack has the same problem: Cover it up and you can't be tracked. Uses a fair amount of power too. And it's very pricey.
Problem with dog collar radios is that they report at a very low rate in order to save battery. This application would require a relatively rapid update rate compared to them in order to reduce latency. Second problem is that when you have many of them on the same "network" it creates interference problems and you can run out of ID numbers.
RTLS (ANSI 371) is low cost (~$55) and long battery life (7 years reporting every 4 minutes on a single AA battery. It can report as often as every 5 seconds. Standard device range is about 1500 feet. High power device (with minimum battery impact) is up to 4.5 miles. It can support 10s of thousands of simultaneous devices without performance degradation, each with a unique ID (over 4 billion IDs). Alarm detection is on the order of 10 seconds. And there are no "service" fees like LoJack and other cellular/satellite systems. You buy it once. Pay once and you own it. Now, if you wanted rapid police/security response, then there is obviously a recurring service fee associated with that, but no air-time charges. The difference is that you only pay when it's needed, not every month per device.
