Hope this helps.
Are both instances in-game or from the dashboard/hub? In-game, stepping out of view should remove that player or you can use the guide (hold out left arm 45 degrees). If you mean the kinect hub, the sign-in tile is on the previous screen. So if you don't have KinectIDs setup for the gamertags, you can reach sign-in there with your hands or voice. Also, recovered gamertags default to auto sign-in which can confuse matters.
It's supposed to be closest to the camera gets control. But if you're both practically equidistant, and both using two different command inputs, that would probably confuse Kinect big time. I wonder what would happen if you simultaneously added a controller to that mix. 3 inputs at once? Red Ring just on principle?
Did you calibrate it at different times of the day using the face card?
No, it's probably as good as it gets. Sorry you spent so much money. . Take it back and put the money towards two 3DS units. Everybody should win with that move. As for the sports game, I hope you mean Kinect Sports. Absolutely do not under any circumstances "play" Motion Sports.
cheers mate, it was in both scenarios that the sign-in was playing up...the main issue was in the dash, but as I said, in game odd stuff was happening. TBH it probably just needs more calibration, I need to set it up to recognise everyone and calibrate in all light conditions and see how it goes. Yes, I did mean the kinect sports title!
it's also surprising how much space it needs, 2 players in a squeeze in our front room (which I always thought was quite big!) so it'll be interesting to see how many are returned/sold on