Hi!!
 
Ok, If you set all clips and tracks and busses to Absolute Time, you can add a tempo change in the middle of all your automation and it keeps your automation where it was based on Absolute Time rather than shifting it all based on measures and beats.
 
This is great!
 
But it still moves my markers. How can I set markers to Absolute Time?
 
Answer
Open markers view and Lock all Markers.

Good tip! Thanks!

Personally, I would appreciate a project level single button solution to change all these things to absolute time for the remainder of the project.
 
It's a pain to have to remember every time you bounce a new clip to switch it from musical to absolute.
 
I'd submit a feature request, but it's having new features added. :-)
http://www.cakewalk.com/Support/contact/Feature-Request