From the news:
We noticed that after the new arena rules came out, people started making arenas with an increasing number of courtside seats and luxury boxes. If you have 5000 courtside seats... they aren't courtside. So we have decided to limit the number of courtside seats and luxury boxes in arenas. Courtside seat construction will be capped at 500 seats, and luxury boxes at 50. At the all-star break this year our builders will sneak in and tear down the excess seats in those few arenas which exceed this limit, refunding all the building costs to those teams. The caps will go into place immediately however on new construction not yet commenced. Also, we have also disabled the arena deconstruction option as was previously announced.