I retired from officiating college basketball after the 2007-08 which was before the use of online officiating assigning was the norm.
Mark, Jr., has been umpiring college softball since Spring 2015 and Div. I since Spring 2018. He has two assigners who both assign NCAA Div. I, II, and III conferences and they use Arbiter. He has a third assigner that uses OfficialHub for two Div. I conferences and uses ZebraWeb for two other Div. I conferences. Only OfficialHub and ZebraWeb require an explanation for a "block".
Why does OfficialHub and ZebraWeb have such a requirement? Who knows! But the guys and gals here that officiate Div. I basketball or officiate/umpire any Div. I sport know that assigners at that level can be very persnickety. They may want to know if you are blocking them to take a H.S. game or a game in another conference. Some do care that your are taking a H.S. game or a game in another conference and some do! That it just how it is in the big city. But at the Div. I level, no matter what the sport, an official's assigners know which Div. I conferences from which he receives assignments and 99% of the time the official has declared a primary Div. I conference.
MTD, Sr.