This isn't the thread I was thinking of but Brian raises the same point:

http://www.sqlservercentral.com/Forums/Topic418501-149-1.aspx

so, should cross database chaining be enabled, people could access objects in other databases without permission checks. People might enable it and not realise this.

I think it is a a small risk myself but worth noting. Do with it what you will.:cool:

edit - and its not so much the owner is SA but the owner of all databases is the same.