Undoubtedly, but to a sufficient degree to determine beyond doubt that any given player was using ? :-
Like I said, a server can’t KNOW a client is using cheat software unless the client component of the game (or other 3rd party anti-cheat software) is running on the client and specifically checking for it.
I’m not sure where it’s been confirmed that DB will be using the Unreal engine, but I guess the pertinent question is will that be possible in this game?
Possible it is with any engine I guess. But no game or engine has that, I have heard Quake Live has something in that direction, but its only rumors I heard. The problem I guess is more the additional work for the server, it either has todo these things at realtime, or afterwards based on a record of the game. Also its almost a complete separate thing, it does not have much todo with the game itself, but I believe if done in realtime, it would allow for some pretty awesome staticistics - besides of the feature to detect cheaters to some degree.
Interesting enough there is already research being done to reproduce human behaviour in games, by using pattern detection systems. So this approach will only be good to detect a part of the cheaters.
Except AI research has shown positive acceptance through simply mimicking what humans do. I’d wager that if you made a system that could detect aimbots someone would code an aimbot to just mimick actual players. 
My personal belief is that other than the obvious of removing any control from the player (closed system or totally server side) you also can limit cheating by getting players to heavily invest in the game.
By that I mean they need an actual, real life, identity registered with the game and that they can do so only once, no new accounts, no reregistering. Being caught cheating means a game wide ban and also your details being released to affiliated game developers, prospectively banning you from many new and old games alike.
This of course is too invasive to be accepted but I honest think that the anonymity and lack of repercussions drives cheating way into a “I was curious/bored” territory. Personally, I’d happily go through a process with SD to have my account locked to my real personal details, I’ve done as much with Steam in purchasing so many games, even if I wanted to cheat I’d never risk it to have a dark mark on my account forever.
Regarding demos:
If you’re relying on demos to find aimbots (they obviously won’t find wall/radar hacks) then you need clients to automatically send demos because what’s sent to the server is comparatively limited. That’s imperfect because the client handles that information but it’s much better than only having server demos and would be useful at least in competition environments as well as with a “Report” style anticheat/antisocial system.
It would be really interesting and possibly a bit touchy if any client could get that demo from any other client at the end of a match.
If you’re saying these are currently undetected, punkbuster would b!tch about some interface utilities so fraps or xfire are probably on whitelists. If you’re saying that’s a security limitation or that they’re otherwise imperfect then yeah, you’re probably quite right on both points.
One point onlive style streaming would have been useful for.
