Well - I have tested the old instruments like Dimension Pro, Z3TA 2 (Not 2.2) and Rapture that all have a Serial number and Registration code in my account. I installed them on a machine that had never seen Sonar (X and Platinum) on it, and also has no Command Center installed - ever. A complete clean install on a machine that has never seen any Cakewalk stuff on it!
All the the programs installed without problem with the serial number. Also - all programs where activated with Registration code (some like Dimension Pro and Rapture had to be run in administrator mode to be able to activate). And worked without any problem in stand-alone mode. This proves that these old install methods are not in any way tied to your computer hardware.
Next test was on FL-Studio that was installed on this computer, and all instruments (Rapture, Z3TA 2, Dimension Pro) worked without any problem in a non-Sonar environment. They did not need Sonar or the Command Center to be fully functional.
So - the only problem seems to be with the applications that only have a serial number and no Registration number. For those we need a reliable off-line activation in the case the activation servers go off-line. And to be honest - I rather see and get them now, before all Cakewalk assets (including servers) go belly-up.