Rich.
I think the reality is that everyone who needs Sonar on both their desktop & laptop simply install their copy on both. The "You can't install Sonar on more than one computer" clause is targeted at large commercial studios should and would be expected to buy multiple licences. I can't imagine Cakewalk for a minute expecting the average muso user to buy 2 copies. If that was the case we would simply be better of going over to Cubase.
Native Instruments allow for 2 separeate installations of their products, Steinberg allow unlimited installs. Maybe Cakewalk should consider going over to the NI system. That way you can remove both registrations and sell on the product if you go over to another DAW. If you buy a MAC you may decide to go over to Logic Pro etc.
When you install Sonar for the first time you click "Register now". You are then sent the registration details which you enter into the box. These details are also stored in "My Registrations" on you Account page. If you subsequently need to reinstall Sonar for any reason you don't need to click on the "Register Now" button again. All you need do is copy the registration details from "My Registrations" in you Account page and enter then in the box provided.
Cheers, CD