I think I can explain that one, maybe.
I used to work for a not-for-profit law publisher and one day our load-balanced webservers which provided free access to the law seemed unusually popular by a multiplier of more than 10x normal (normal was in the order of 700K hits per day).
Examining web log files and checking IP addresses, it became apparent that apart from all the robots, there were a number of large Telco ISP content caches which were refreshing their cache of our site with 1,000s of concurrent connections.
The caches proved to be another problem when users were being served outdated (by up to a year) law because smaller ISPs were not refreshing their content caches regularly or at all.