That is an excellent recommendation - however, you must also realize that TruTrak only holds contact information for a small number of their users. Others, who bought their equipment for vendors, they know nothing about.
They do have a public site and an excellent forum. They are also selling their equipment as "experimental." I'm all for encouraging them to take a more proactive role, but my original point is that as "explorers" we likewise have a responsibility to keep abreast of issues involving every piece of experimental equipment on our aircraft.
There is precedent for this in the A&P world, where the mechanics are charged with seeking out ADs and service bulletins for each piece of equipment they service, and also when performing an aircraft Annual Inspection. I'm sure it is also true for Avionics shops.
If our goal is to encourage TruTrak to notify their customers, the simplest suggestion I can think of would be to encourage every user to sign up on their Forums, and ask the moderators to automatically email everyone on the Forum list whenever a new bulletin is released. I know they post in the forum; it wouldn't be a big deal for them to also email that info to everyone signed up.