Figured I would weigh in, since several of the images on the Photo Salon page were mine, and I haven't seen a post from any of the other featured entrants.
Looking over all the print and photo salon entries, I don't see anything that looks like digital "trickery" to me. Things have been sharpened, tonally corrected, maybe selectively lightened or darkened in shadows or highlights, etc....all those things that just try to render it as the eye sees it. Sometimes that helps a lot in making up for poor exposure, etc. But "the line" is pretty clear between digitally manipulated and enhanced, just ask the question: Was everything in that photo really in the scene when shot? This invariably means elements of another photo were added, BUT ONE THAT WAS NOT SHOT IN THE SAME PLACE. You might add multiple exposures of the same scene, as in HDR; you might stitch a couple photos (my guess is that's what was done in Sean Robert's beautiful winning print; you might take a piece out of another frame taken at the same spot, with better lighting, expression on the model, etc. and replace part of your frame. All these are legitimate as they don't lie about what was there: they just portray it in the most optimal way.
Years ago, I believe I had the first digital composition to win a Salon Medal. It was pre-digital camera, but I combined some slide scans to put a diver into the drop of a soda straw. Then I output it on a film recorder. There were more than a few cries of foul play thrown around after that. Yet no one could contend I was trying to represent it as anything "real"...it was very obviously trickery. It was even entered in the humor category (and may be the only time a humor entry had won a medal, much to my shock). Later the "enhanced" category was rewritten to direct such trick shots into that area. But of course, only one overall medal has ever been given, not one per category. The latter is just a way of being up front about an image. BTW, cavers without clothing go in the same category...
The idea that certain manipulations should or shouldn't be allowed would be pointless and unworkable, beyond the "real or unreal" test. The same issues apply with slides as soon as you place them in a scanner: choices must be made about sharpening, color balance, etc. All these things are done, and can be variably controlled, in most digital cameras these days. So it would be pointless to say you can't modify a digital photo being entered...every camera applies some degree of settings to every photo made, and its not hard to figure out that you can really add some pizazz by turning up the saturation applied by the camera.
I prefer doing all these things myself in Photoshop, and have all the supplemental processing in the camera turned off. Shooting RAW images is even better as no processing is applied by the camera at all. Besides the increase in dynamic range, the other reason I shoot them is for control over white balance, AFTER the photo is shot. As mentioned earlier in this thread, is easy to set white balance on most any camera (usually just some fixed presets) but what wasn't really well pointed out its that its not so easy in post-processing. Say you were set on daylight and used white flashbulbs for your photo. They would be very orange looking! Photoshop has no simple "adjust white balance" button other than a crude thing that finds the lightest area and defines it as white...and adjusts the rest accordingly. You get some really entertaining results if your photo doesn't really have a white spot. But in a RAW photo, you can adjust the white balance to a new numerical value as you open it. Very handy, because you can see the effects, and then apply the same to a bunch of photos if they are off.
I've rambled on enough...happy shooting!