I'm sure you can, but anymore why would anybody want to? It's been a long time since any web site "demanded" IE. I've been on the MS site many times with Firefox with no problems.
attempting to introduce a representativeness error is hardly helpful. Just because you can't think of a good reason doesn't mean that nobody else has decided to change their UserAgent string; in fact, it's naive to make the assumption that just because you are unable to think of a reason for it that nobody does it; a quick extension of that logic reveals that in fact everybody in the world uses firefox, for the sole reason that you cannot think of any reason to use any other browser.
Salmon Trout's point is that while the user is implying their statistics are accurate, they are not. Any number of anomalous errors could be introduced by any number of people spoofing and using a UserAgent string that doesn't match their browser. Taking it on faith that nobody anywhere that visited that page changed their useragent string is wishful thinking. This is, again, completely forgetting about the various Command line programs that ST noted; again, just becaue you don't use them doesn't mean they aren't widely used; wget, curl, aria2c, an so on have to give something as a useragent and they usually go with either IE's useragent or nowaday's Mozillas. Whichever one they choose, they are weighting site statistics in favour of that browser- again, That's Salmon Trout's point here; Curl, Aria2c, and wget are not browsers and assuming that the statistics of a site magically don't include such tools which are otherwise indistinguishable from actual users that are browsing the site is. That's why ST noted that the figures are indicative but not exactly accurate.
