[Plugin: Popularity Contest] Problem with overstating blog post hits

Monitored posts. At 7:46pm popularity counters increased on the top 3 posts. Reviewed the server log this am. There was no activity on those posts during that time frame. 2 of the 3 that incremented had no activity at all during the day. The 3rd was picked up by a bot later in the day outside of the time slot monitored. Why/how did the counts increment?