Sometimes when I have a unstable connection, everything may seem normal, but I cannot see the others for some seconds. Then after some time everything's back.
I use to use the chat function to test it. If I'm semi-disconnected like that, my test messages (usually "cn" for "connection?") won't appear on the screen.
Also, if I bomb carriers or hangars or shoot at the zep when this happens, it may seem I'm successful,but it's not real. The points aren't counted and the hangars reappear when the connection is reestablished.
The worst thing is that I may have been shot at by planes invisible to me, so that when I reappear in the game I may discover that I'm in flames and going down.