A player cannot be logged into Game Center from multiple devices at the same time, correct?

Question

A player cannot be logged into Game Center from multiple devices at the same time, correct?

Answer 1

Just logged into the same account on my iPhone and iPad. So you can be logged in at the same time from multiple devices. You can also send invites to different players while logged in and I successfully started a match with my game Cee-lo while logged into two devices.