I had same problem, Forums People Gave me a answer, so same thing i m telling you.
Your Situation..
Account 1: You F1'ed your MND in Space thus, it remains on server for like 60 sec. So it means you are STILL PLAYING ON THE SERVER FOR NEXT 60 Sec.
Now if you go to your second account.
Account 2: You will not get that Message "That the account is already logged it", you will see the Ships but if you try to log the Ship YOU HAVE 2 SHIPS in GAME in that 60 sec interval. Hence MULTIBOXING (Cheating)
