In the pre-computer dark ages...
Before a show was put on sale, one ticket for every seat was printed for each performance. After the initial curtain went up, the
box office would count the
deadwood, subtract that from the capacity, and prepare a
Box Office Performance Report. Among the
line items: full price tickets sold, discount tickets,
comp tickets,
etc., was a
line for
House Manager's Count. The
House Manager /Ushers counted every stub handed to them by a patron. The HM's count was equal to or less than the
Box Office's count (to factor in "no shows"). If the
House Manager's count was greater than the
Box Office's, the
Producer had a problem. We don't really care about how many people are actually watching the show; we only care about how many tickets actually left the
box office.
Today...
With print-upon-purchase or print-on-pickup or even E-ticket ticket-less systems, it's much more complicated. Rather than collect stubs, most venues in Las Vegas equip their "
ticket taker s" with barcode readers, which transmit the data wirelessly back to the
box office.
But the principle is the same--there better not be more butts in the seats than the
box office thinks there is, 'else something fishy is going on.