Pretty sure of the two (?) five day boarders I know of at McD for lax they are both MD residents who didn't want to drive the commute every day (you have to live within 90 miles). Neither are fifth year seniors, and both are MIAA eligible on age. Not sure the epidemic here. Also they've had boarders since 1873. If it's a lacrosse arms race on boarding, they started early!
BL pulling from further away geographically with seven day boarding but they are the outlier. No idea how many kids at CHC coach/family board but it's not usually a large number. | 
