The longer version
A court block is a reservation with no customer. Staff use it to close a court for resurfacing, hold four courts for a Saturday tournament, or keep court 1 free for the coach from 16:00 to 18:00 on school days. Players see the court as unavailable.
Blocks matter because they are how the club’s own plans compete with bookings. Every block on a peak hour is revenue the club chose to forgo, which is fine when it is deliberate and expensive when it is forgotten.
The mistake is the block that outlives its reason: the maintenance finished on Tuesday and the block runs to Sunday. Give blocks a reason and an end date, and review standing blocks each month against occupancy.