Mackintosh's Corollary
Related to Lloyd Webber's Law Of Temporal Positioning. The law states taht people who arrive at a theatre after their performance has started will always have seats in the middle of a row, causing as much annoyance for the other theatregoers as possible.
The Lyttleton Theatre at the NT (London) seems to know which theatregoers will be late, and invoke Mackintosh's Corollary on purpose.