HuskyPup - 6:44 pm on Feb 21, 2013 (gmt 0)
Suggesting the guy left the pages reloading and could have waked away for a coffee. The entire thing lasted for about 40 mins.
Yep, I had this happen a couple of weeks ago with 3 requests per second for several hours, whatever it was just seemed to lock onto my site and wouldn't let go. Obviously it generated tens of thousands of extra impressions in my logs, they were HUGE, however nothing extraordinary was recorded on AdSense therefore I assumed that Google "knew" something strange was going on and just dismissed them.
Did your AdSense charts show anything different for that specific period?