I would not call the 700XX a high RPM four stroke, so it should not be a problem at all, but the CRF's do have this happen. It is just the way the breather is designed in the valve cover. My 2003 CRF from the factory had a little tube on the breather with a plug at the end that would collect the oil. After every high RPM ride, the tube would be full of oil. Since the CRF's only hold about a two thirds of a quart of oil, I could see that a aggressive rider could blow out enough oil to hurt the motor in a day of riding.
My TRX450R's will blow a little oil out the breather also after alot of high RPM riding. No where near as bad as the CRF, but it does do it. It is pretty normal for the Honda 450's and 250's, I do not expect it to be a problem at all on the 700XX.
Doug