Just signed up for 2nd account. Called Diamond desk after I merged accounts online, told them what I was trying to do and they helped me do it. The rep put me on hold, came back and said he had verified everything was in order as far as me receiving the promo. I told him I had already completed 8 stays during the promo period and asked if they would count (retroactively). He put me on hold again then came back and said they would. Within 10 minutes my primary (Diamond)account number was credited with 50,000 bonus points. I never had nor was I asked for an AC acct number.
Within 20 minutes of logging onto to Flyer Talk, I had 50,000 points in my primary account. Thank you for posting this!