1. Wasn't there another thread on this?
2. As sgreenwell notes, in many states it is customary for varsity teams heading into the playoffs to bring up their entire JV (and sometimes freshman) rosters. Few or none of these players would have dressed for three varsity games during the season.
At least at one point in Michigan there was no roster limit for HS football teams in the playoffs; I remember some teams dressing out 90+ players like college. One game was 30+ points in the second half and they started running the JV and freshmen, in complete units, just so they could say they played in state semifinals, etc. Funny thing was, the freshman team held its own.
I seem to vaguely remember there may be a 65-player limit now, but I could be wrong.
With lots of schools statewide struggling to get 20 people in uniform, it's probably way down on their priority list.