Since Pennsylvania was previously only protecting bucks with antlers less then three inches, before the change to the current antler restrictions, if there was any chance of high grading in this state it already happened a long, long time ago. Now we protect more of our better bucks then what we have EVER protected before, so if anything we have started the steps of reversing the past more significant potential for high grading by only keeping the really short antlered spikes.
That simply is not true. The 3" spike rule was designed to protect BB from being harvested as antlered deer, and it was not designed to protect 1.5+ buck. We are now harvesting the best of the buck in each age class while protecting those bucks that are inferior for the rate of antler development. That is the very definition of high grading.
Even with the 3" spike rule there was no protected class of deer, BB and inferior 1.5 buck that didn't have 3" spikes were legal as antlerless deer. Now inferior 1.5 buck and inferior 2.5+ buck are protected from being harvested except by juniors and military.