Aliasing can be an issue, but there are a number of factors governing how serious a problem it will be. If you shoot with low or no sharpening you can reduce any effects, and if you want shallow DOF (a big draw for many) then it likely won't be an issue. If you take a look at my sample video @ 0.30-0.35, I was trying to produce aliasing effects by filming flyscreens, but couldn't. That said, here's an example of bad moiré on a 550D:
The first and last shot of this video has some more typical (ie. not so bad) jitter in the building in the top right corner:
http://www.vimeo.com/9840579
Somewhere else, someone mentioned that they had to push sharpness to +2 to produce moiré effects. I'd like to see more tests too, but it's at least somewhat avoidable.
