Who honestly gives a rats *** about **** like this? Capello worked in Milan, Juve, Roma, and nobody batted an eye. Managers don't have as much as flexibility as players to avoid working for rival clubs, they have go where the job is. Any person that's not a complete ******* understands this.
It's completely different between ManUtd and Liverpool. Even though there is lot of rivalry between Milan, Inter, Juve players usually move between these clubs. There are transfers and a very big ones too. That's not possible between ManUtd and Liverpool. Last player moved between these clubs was in 1964.
It's common in Italy but not in England.