Team games with resources, like water connected by "rail" to my teammate's HQ, were going to my teammate, even when I wasn't sharing water resources.  I got no blimps, and the water resource looked like it was connected to an HQ, which it kind of was to my teammate's, but, like I said, we weren't sharing, yet the other guy was getting the water.  The blimps started flowing again when my teammate got bought out.

This was a team game with the AI, who never shares, but I get that.  I was just trying out the sharing interface really, and then ended up playing a whole game.