For over a year now I've been operating my corporate website using 2 servers, one on port 80 and the other on 443. Site files duplicated for each one. No, I haven't had a redirector from http to https. I originally set up the https based on talk more than a year ago that browsers were going to throw up warnings and scare people away from http search-result links, or the search engines weren't going to throw up any more http results if they can help it. The https site was more of a curiosity for most of this time - only the big search engines were hitting it. Over time I began to ignore the logs - nothing interesting there. The hits to the http site were still coming in as usual.
Then about 2 weeks ago I started noticing a steep drop in http hits. I figured well, it's a weekend in july, so people are on vacation. But it persisted during the week days. So I looked at the https logs and yup - there's where the hits are, with google referrers. I don't know if bing is doing the same - I don't get many hits from bing as it is, but I'll have to have a close look at all my https logs now going back to January to see what I've missed.