I had a similar problem with my bike although I don't live in the States. Theft insurance was a whopping 1500US$ a year!
So I bought a GPS tracker. The one I now have has several functions.
1. It works via SMS. On one side you need GSM coverage which is no problem over here. Looking around you can find really cheap SMS providers. Plus you have no monthly excessive fee.
2. It sends messages to up to 5 different GSM numbers.
3. You can program alarms for moving (a minimum of 500 yards not to trigger false alarms), speed (if you give it to your son), geofence (you determine a territory where the bike can freely move without triggering an alarm. Plus power cut and low internal battery power alarms.
4. You can always "ask" his position by simply calling its number. It sends back immediately an SMS with the position.
5. You have a hidden emergency switch. This sends a message with "Help" and your coordinates to the stored phone numbers. You would be surprised how many people have incredible problems operating a mobile phone after an accident. Saw several times that they could not unlock their phone when help was most needed.
6. You can listen to whatever happens around the receiver as it has a small microphone too.
7. You can set the frequency of the messages freely. From every few seconds to hours between messages.
8. When there's no GPS coverage it will give the last good fix, e.g. the entrance to a covered parking lot.
Last, and best, you can switch a relay by phone. You connect this to the kill switch. In case of a stolen bike you get rather a quick alarm. So you call the cops, tell them the current position and just wait a few minutes till the thief is somewhere on a stretch of highway without exits. Then you trigger off the kill switch.
All you have to do then is to wait for the LEO to bring back your bike.
This should work well. Did it at least when we tried. The unit itself is the size of about 2 Zippo lighters, not waterproof but you can put it in a plastic bag. The separate waterproof antennas give very good reception even through the fairing plastics.
This unit cost around 130$ shipped, so it's a cheap insurance IMHO.
What you must consider is the limited number of places on a bike. BUT a thief has not much time and he will most likely try to get away as fast as possible and not try to search for hidden devices first.