I'm getting email from Empire Sportsbook when the only book that had that address was Vwager. I just got two things in the mail from Bestline sportsbook which looks exactly like the mailing I use to get from BOS.
A horseplaying friend also got the solicitation from Bestlines (30 % bonus) and asked me about it - I asked here yesterday but no responses. It's got B- rating from SBR (which is OK) and is still operating, so it can't be part of BoS.