Has anyone got the remotest idea who these people are?
They appear to own the whole /24, though all crawling to date is from the narrower .192/26 subsector.
UA: Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 6.0)
But see below.
Far as I can make out they belong to an outfit called Fieldtech. The one in Idaho, not to be confused with the (probably) several dozen other companies with the same name. They ask for and appear to obey robots.txt, and generally crawl at a leisurely pace. ("Appear to" = they've only gone two steps from the front page.) I've met them twice: once in the first half of January, and again a few days ago.
Alongside their ordinary crawling, each visit has included a block of exactly 18 (eighteen) requests for the same interior page. For these they used a different UA
which got them blocked. Eighteen times in rapid succession.