Where? You haven't provided any proof that Ubi ever indicated any such thing.
1) They don't care.
2) Everyone is correct.
As I stated earlier, they don't list an release PR for everyone that licenses UE3. If you think they do, you haven't been following the engine very long.
When I saw any article about R6 and Mark Rein I always read "using Unreal Technologies" and I rarely read UE3. I mean look:
However, do note that Epic ONLY has a PS3 version of UE3. There is not a UE2 or UE2.5 for ANY console, only UE2X. Also note that he is comparing it's release schedule to UT3, a UE3 game.
Nothing more I need to say on that one.
And my booklet
doesn't even mention Unreal Engine. So now I guess it doesn't use it at all?
It doesn't... except when it comes to middleware

Plus, all the evidence is against what you are saying. The only way you'll convince anyone it is UE2.5 is by having someone from Ubi come in here and state that, with proof

Maybe you're thinking of Raven Shield
I'm confused – which engine is which? -
source
The Unreal Engine encompasses three generations of technology, each focused on a major generation of console platforms and PC hardware.
Unreal Engine 1 powered Epic's original Unreal and Unreal Tournament games.
Unreal Engine 2 powered Unreal 2 and UT2003; Unreal Engine 2.5 – an enhanced version of Unreal Engine 2 – powered UT2004; and Unreal Engine 2.X – an Xbox-exclusive enhanced version of Unreal Engine 2 – powered Unreal Championship 2: The Liandri Conflict.
Unreal Engine 3 is the current technology, aimed at next-gen consoles such as Xbox 360 and Playstation 3, as well as DirectX 10-based PCs. UE3 powered Epic’s Gears of War, as well as Unreal Tournament 3.
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You do not seem to understand that a Game Developer does not just pickup a Unreal Engine License and make the game. They tweak it, modifiy it and sometimes, the change it so much that it shouldn't even be called Unreal Engine. So even if Epic doesn't have anything else than 2.X for COnsole games before the 360 doesn'T mean that the other devs do not have a UE version that works on it.
Ubisoft used a heavily modified UE 2.5 version for R6 lockdown and Splinter Cell 1,2,3 (next gen) and 4 (next gen). People were saying that UE 2.5 couldn't handle a 360 game, what is definately false.
So if they can have Splinter Cell 4 on UE 2.5, what would they care about spending $75 000 for it, without counting that they would have to modify it back???
On their web site, there is no information about Rainbow Six: Vegas as using the Unreal Engine 3.
Plus, this is interesting:
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Proven Technology
Multiple UE3-powered games are currently in development at Epic and by our licensees, targeting a diverse set of genres from fighting games to MMPOGs to shooters. The technology was used to power games such as Epic’s recently-released Gears of War and the upcoming Unreal Tournament 3, as well as many games by licensees that represent some of the best studios in the industry.
For more Unreal Engine 3 licensing news, including announcements of support for Sony’s Playstation 3 and Microsoft’s Xbox 360, visit www.epicgames.com.
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What means that if R6 Vegas was using UE3, it would be linked somewhere on their Official Web Site, but it's not.
So if you were Ubisoft, actually making Assassin's Creed (spend a too much money on it)...
plus Ubi made their own Engine what includes Multiplayer features as you can see on IGN for Shawn White Snowboarding so they can do all that stuff themselves, and that you actually have efficient programmers and a heavily modified version of UE 2.5 that can handle 360 games would you seriously buy a UE3 license? Definately not.
So, no official proof on both Epic Games or Ubisoft Montreal websites that specify that R6 Vegas used the Unreal Engine 3, only powered by Unreal Technologies. No license news, nothing. The only valuable proof is suppsoed to be the name of you file extensions? Ever asked to a programmer if you could just change the file extension name LOL while tweaking the editor?
So no information on a UE3 = something else than UE3 what means a heavily modified UE 2.5 for the Tom Clancy's Franchises.
http://www.eurogamer.net/article.php?article_id=72234 - 25 January, 2007
Mathieu Hector: The engine used on SCDA only uses elements of the Unreal 2 pipeline, mostly the tools set. We have been improving the runtime engine for several years, to finally keep only a few parts of the original code. For instance, the rendering engine is closer to Unreal 3 than Unreal 2. Additionally, the engine has been adapted throughout time to fit with Splinter Cell's gameplay mechanic, which is not really a first-person shooter.
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I know the image is small, but I'm sure you already saw this game. Compare it to Vegas it's really close. If they actually had 2.5 version already close to UE3, I'm sure you can get the easy conclusion that their Engine for R6 is so close to UE3 that they can call it UE3 if they did without even buying the UE3 license so it means... it'S not UE3, it's UE 2.5 uber modified.
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If you do confuse Ubisoft & Brothers In Arms Hell's Highway: Gearbox Software's... they have UE3 but they aren't Ubisoft, Ubi is only the publisher & distributer.
Brothers In Arms Hell's Highway: Gearbox Software's critically acclaimed squad-based WWII shooter launches into the next generation of gaming with amazing graphics and cutting-edge game play features powered by Unreal Engine 3 (not Unreal Technologies)and a completely redesigned online component. As Matt Baker, lead a squad of real soldiers who think, relate and fight together through the brutal trials of the dramatic Operation Market Garden.critically acclaimed squad-based WWII shooter launches into the next generation of gaming with amazing graphics and cutting-edge game play features powered by Unreal Engine 3 and a completely redesigned online component.