the best kind
Seriously, though, a
captive audience is exactly that:
one that can not leave. This tends to be a
bad thing, since people usually value their
free will, but it is the origin of the idea that a
performer or
performance can be
captivating,
i.e. make people not
want to leave.
Captive audiences are often found in:
elevators
the lairs of evil super-villains
children's piano recitals
and other nefarious locales...