Admit I have no experience with going down on new tires nor finding them slippery. Probabbly more of a function of my less than overly aggressive riding style but if as most claim they need to be scrubbed in for safety reasons I think the entire motorcycle street tire industry could be held liable for all the reported faceplants.
We live in a horridly litigious society and I have never heard of anyone bringing suit aganist a bike tire mfg for tires that were not "ready for the road" as delivered.
Seems to the uninformed that if they needed to be scrubbed this would be done by the mfgs before delivery, or it isn't necessary. Simply stating that one should "take it easy" for the first 100 miles is not enough to ward off nor win a lawsuit if in fact the tires are inherently more dangerous during the initial run in.
Possibly this was the case 20+ years ago but I'm just guessing here that with 2013 manufacturing technology that it does not hold true today.
Go easy for the first 100 miles to get the tire thru a few heat cycles and get use to the different (and improved) profile, and rid it of any mounting grease/soaps, etc. Call it scrubbing in if you want.
Any day on a dirt road is a great day