Slacor Fair enough.
Recently around that time my Macbook battery accidently ran flat and reset the time due to turning on by itself while in bag due to a USB NIC I use that supports WOL. Turns out they use the main battery for the RTC clock,
I guess the reason why this occurred is I manually set the time as I had no network access at the time (travel) and it didn't resync properly when coming back online.
Sounds like a good proposed fix.