Four hours ago on an ad-free site hitting from:
msnbot-157-56-1-18.search.msn.com
(a.k.a. 157.56.1.18)
robots.txt? Yes BUT with NO UA (so no-go):
"GET /robots.txt HTTP/1.1" 403 "-" "-"
The UA appeared when it went for root in the same second:
"GET / HTTP/1.1" 302 "-" "BingAdsAdInsightBot"
FWIW:
Google sez: "Your search - BingAdsAdInsightBot - did not match any documents." Hmm.
And nada re Bing, ditto Bing Webmaster Tools: [
bing.com...]
Momentary test, maybe?