Jeremy
in memoriam 1991-2020
No, here's the headers sent via Chrome when I've sized down the site to a mobile view in the browser:
There is no way for a server to reliably determine if its going to be mobile-sized.
Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Cache-Control:max-age=0
Connection:keep-alive
Cookie:[x]
Host:xenforo.com
If-Modified-Since:Tue, 25 Jun 2013 22:09:51 GMT
Referer:http://xenforo.com/community/
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.116 Safari/537.36
There is no way for a server to reliably determine if its going to be mobile-sized.