Good thought, Dooley36. That does add a 'shades of...' perspective to the situation. Tessio aided Barzini in the past, now Barzini returns the favor. Brothers bound by treason.
However, Barzini being the kind of Don that he seems to be, I can't see that he would honor the deal for long. He'd look to consolidate his power and assets fairly quickly I would imagine.
I maintain the thought that if Tessio had been successful, then Barzini would have found a way to off him relatively quickly, whether via "accident" or outright execution, to eliminate a potential problem down the road since if Tessio is willing to sell out the Corleones due to them being weaker (or, rather, giving that impression) then he would do it again to Barzini if the Barzini family's power waned.
