[smurfgirl]

I think it's usually a good idea to let teams know you want to pick them in advance. If they also want to work with you, it allows you extra time to start strategizing and discussing your potential third alliance partner. If they let you know in advance that they're not interested, that leaves you time to go with a backup plan and start this process with another team. It is also useful to know if a team does not want to work with you, because it is a viable and acceptable strategy to use that information to break up a potential powerhouse alliance.