Agree with Vermontster. for deer, there is hardly a wrong set up. I have gotten pass thru's with a 45 lb bow and I suspect I could do it with high 30's, as long as you are taking reasonable shots for that equipment. For larger game, or for long range shots, then the discussion is real. I believe they (law enforcement)use the bow poundage as a rule of thumb because it is clearly and quickly evident in the field. It is something that can concievably be controlled. Can you imagine having to carry documentation with you describing calculations of your bow's efficiency and validated using particular draw length, arrow weight, string, etc. etc. so that the officer can review them in the field to determine if you met the stated minimums ?
ChuckC