Actually, you are responsible for your copy of UT. The copy of UT has been globally banned because of an aimbot. Nobody, if you looked at the appeals have been unbanned.
Also you should have a look at the EULA as well from Epic, at article 5.
http://www.epicgames.com/ut2k4_eula.html
[quote]5. CHEATING. Nobody likes a cheater. It's a disgraceful way to earn a win and really is an insult to those players who earn their wins in on-line games the old-fashioned way—WITH TALENT. We're pretty hard on cheating in on-line games using the Software because it sullies the overall gaming experience and is JUST PLAIN LAME. With that in mind if you are caught cheating in an on-line game using the Software we will immediately and permanently ban your CD Key. At that point this License Agreement is automatically terminated and you must immediately delete this software from your PC. Failure to comply with this last bit (deleting the software) may bring on the wrath of the lawyers. Trust us…you don't want that.[quote]