Since we switched to the current generation of AI products I'm less and less convinced the Prelude is necessary (and it is a potential carcinogen - don't snort the stuff!). I still use it because I have a bunch of it and it takes almost no time. Products like AI or Walker Prelude take substantially longer to use, but they do a much better job.
In response to the original question, I concur with the others that new LPs should be cleaned. Newly pressed vinyl contains mold release chemicals which, if not removed before play, gum up the stylus, muddy the sound and hold onto airborne dust and other contaminants.