Maxer (12/19/2016)
I could sign the stored procedure with a cert but...that's a PITA....
That's probably the safest option, and when you do it once, it becomes quite easy after that. I regularly use a certificate for this kind of cross database query in a stored proc.
https://www.mssqltips.com/sqlservertip/3336/how-to-use-module-signing-for-sql-server-security/