Bots that impersonate Googlebot
Anyone can act like a bot just by using the Googlebot useragent in a request. Sometimes crawlers do that to see what other bots might see. Sometimes it’s to circumvent robots.txt directives that apply to them, but not to Googlebot. Sometimes people hope to get a glimpse at cloaking. Whatever the reason, these kinds of requests can be annoying since they make log file analysis much harder.
Motivation for this excursion: