Empty pixel log files set the lastV2PlaybackTime to '1969-12-31 16:00:00'

I ran a pixel log file where all the rows were getting filtered out, and in the playback output log, you can see where the date is set back to 1969 when this happens.

2011-05-17 05:19:39.066 (4) [P1T1]: spike: SQL->[select * from `pixelPlaybackStatus` where (`siteID`=308) limit 1]

2011-05-17 05:19:39.074 (4) [P1T1]: time=0.0080

2011-05-17 05:19:39.074 (4) [P1T1]: Query executed in 0.008s

2011-05-17 05:19:39.102 (4) [P1T1]: Record Loaded

2011-05-17 05:19:39.106 (4) [P1T1]: spike: SQL->[update `pixelPlaybackStatus` set `lastV2PlaybackTime`="1969-12-31 16:00:00" where (`siteID`=308) limit 1], genflags=no

lastV2PlaybackTime was set to '2011-05-10 10:00:00' before this was run.