Those of us who upgraded to Production Suite in August (to get the free X2 upgrade) also got the free strings...although we really didn't know if we'd qualify for it. I think it's great that Cakewalk is continuing to let others have it too.
Some may feel that it isn't fair, but...Cakewalk never said that the "early adopters" were the only ones who would receive the strings. They just said pre-order your upgrade and receive a free download of the strings.
People who did the early adopter thing just assumed they would be the only ones to get it.
Those of us who upgraded to the Production Suite actually paid our $100 before the "early adopters" did. But we also got rewarded with the upgrade to the full version of Z3TA+2 and the PC4K expander/limiter (which was a part of the Production Suite).
Again, I think it's nice of CW to allow everyone who is upgrading to X2 to get the free strings download. It's a nice gesture on their part.