An overtime period is a gift to spectators and a problem for the building. Every operational plan for the night was written against a scheduled finish.
Staffing is scheduled to an expected end
Ushers, security and cleaning crews are rostered against a projected finishing time, often with shifts that begin ending as the fourth period runs down.
Overtime extends those shifts, which has cost and, in some cases, labor rule implications that supervisors resolve in real time.
Arenas hold a contingency roster for exactly this. The staff released early on a blowout night are the same ones retained on a tight one.
Concessions have already begun closing
Service points typically stop selling at a set point in the final period, and stock is being broken down before the game ends.
Overtime creates demand at outlets that are already closing, and the decision to reopen is rarely worth the labor cost.
Most venues therefore keep a small number of outlets open later specifically as a contingency, rather than attempting to reverse a full closedown.
Transit and traffic plans slip
Local transit adds service against a predicted egress time, and traffic management staff are deployed on the same assumption.
An overtime period pushes the crowd into a later window, sometimes past the point where extra service was scheduled.
Venue operations centers communicate directly with transit control for this reason, and an overtime notification is one of the standard messages sent.
The crowd changes character
A tied game at the end of regulation holds a crowd that would otherwise be leaving. Attendance at the final buzzer is close to full rather than thinned.
That produces the loudest sustained period of most arena nights and the hardest egress of the season for the same building.
Operations staff describe the two effects as inseparable: the best atmosphere and the worst departure arrive together.
Why the plan is written in advance
Improvising an overtime response is unreliable, so arenas run it as a defined contingency with named owners for each element.
The trigger is not the overtime itself but the closing minutes of a close game, which is when the contingency is activated.
Buildings that do this well produce no visible change at all. The spectators experience an extra five minutes of basketball and nothing else.

