well yeh.. adspace on the site! lol
if they use torrent to distribute, then they would be acknowledgin that p2p is a legitimate delivery method.. ( though novell uses it for opensuse,and also many open source projects)
when XP sp2 came out, they had sen out cease an desist letters to a coupke sites that seedin it, ( even though is a free upgrade.. and the sites weren't warez oriented )
i suppose too that they probably afraid that if they offer it via torrent some dude go end up injectin somethin in the file, and wham! a million zombies, and microsoft to be blamed..
yeh they could use checksums, but to the average user( and is ms.. they haev PLENTY avg users) md5 might as well be greek
side note.. any time someone tells me how 'bittorrent have plenty viruses' i feel to strangle them..lol