I don't have useful insights into the environments that still use IE6, but I can imagine some friction.
I am personally opposed to web sites that say things like "you have a really horrible browser, download this one...". (Also I still sometimes see sites that say optimised for Netscape 4.x or whatever, another way to get a great laugh!!) I consider a message from your page to download Chromeframe in that same light. Imagine if somebody on a slow connection goes for it and then loses a lot of time while it all happens (and maybe fails). Having them hate you might be the least of your problems. If they come after you with a baseball bat can you be entirely surprised?
If I were ever to use this I'd probably detect browser at the server and deliver different content. (Which is a whole other can of worms.)
A good thing is that it is fully opt in. If you do nothing you are not involved.
If I found that a site was getting an important number of IE6 visitors with the chromeframe already there it might be worth considering.



