Someone in another post (I can't remember which) gave a way to ensure a way to reauthorize SONAR and some Cakewalk VSTs:
If you take certain steps now, you shouldn't have to worry about the servers being offline to activate the software. Most of the software that was part of SONAR didn't require online activation. According to the Cakewalk knowledge base on the following items required activation:
Music Creator Pro
Rapture Pro/Sessions
SONAR Platinum/Professional/Artist
Z3TA+ 2
CA-2A
Cakewalk provides offline activation. Install the software. Once it is installed, click on the option for offline activation. It will create a file. Upload this to Cakewalk. It will generate an activation file. Download this file and SAVE IT. This is then used to activate the software. If you save these files, you can always come back and activate the software without the need for internet access or Cakewalk servers to be active.