I have the same problem ! And I thought I was alone...
Mine turns itself off randomly but always at the bottom of the hour, ie 13:30 or 19:30.
It only happens when I watch satellite TV (I live in France). Never when I watch a DVD. So it must be related to the satellite box... but I changed the satellite box a couple months ago for the latest model, and I still have the problem -- less often though.
It's been going on for more than a year and nobody has a clue. A B&O technician came over to my house but couldn't find anything wrong.
Can you email me your name ? I'm going to write a letter to B&O describing the problem, if I can mention that somebody else has the same issue, maybe they'll take it seriously.
Thanks.