Disklavier

I have a new Mark IV, it's been in my living room now for about three 
weeks (turned on all the time).  The other day, with nobody else in the 
house, at 2pm it started playing.  I was upstairs and heard it start, 
when I came down to investigate it was playing normally (as if someone 
had pushed Play).  Anyone ever have this happen before?  Any ideas?  If 
it happens again I will call my dealer for support but I was curious if 
I was alone on this problem of it someone else had experienced (and/or 
solved) it ... 

Thanks!
Jason