Don't forget that US Elites and other Star Alliance Elites can poach the CO premium seats also!

The whole E+ access for Star Alliance Elites (Golds and Silvers) has been a source of contention since UA eliminated access.

IMHO if UA places and same seating restrictions (E-) on Star Alliance Elites as they do to the general public, then the fellow Star Alliance carriers should follow suit as well.

US and CO (as well as others) should not permit UA Elites (or any other Star Alliance Elite) access to the premium (or choice) seats.