you ever hear of Shell drill? its the defensive 101 drill that anyone who has ever coached knows is a cornerstone of instruction. It shows that if you are two passes away, that you have a foot in the lane to be available for help. We don't usually do this (other than the hedge, when the 4 man is on way to paint to cover 5 man roll). Hence no one "can get into lane", bc they are in deny position on their men, irrespective of being 2 passes away/foot in paint. It's a choice. Quick, name me the last charge you remember from a help defender. I'll wait. We are coached to stay on shooters at 3 pt line, so usually no 2 pass away-help in lane. During the tourney we do change this up, most notably against Arkansas