Something similar just happened to me. It may not be related because it sounds different but you never know... It sounds like the others were actually watching their RADAR while I was not (at the time)
I had my RADAR up and running. Eventually, I got distracted with what I think most people would call real life...
When I clicked back on the game, someone was there. I clicked the attack log to see if they were waiting to for me to attack first or did they just land there and ran out of moves? I clicked on the attack log to see if they had hit me... Sure enough they did... around 45 minutes prior...
Why would they be sitting there? hmmm... When I went to click on them, the authorization window popped up, I clicked on all the gold and when that screen went away, the person was gone...
If you look at the logs here is the time info from the attack... You can see if that person moved right away or not...
Date & time of attack 21 Apr 2007 @ 06:26:45
Elapsed time since attack
( hh:mm:ss) 56 mins
Using IE 6 SP2
Could this somehow be related to the authorization routine? Or was did it happen before that was in place? Or possibly the new PTW clock in the attack window? Is 17 April the first time this problem reared its ugly head?
I think the assayers are doing it maybe they have psychic powers that we don't know about or maybe it is a magic pearl!!!!!
(sorry just kidding)
Hope this helps...