A missed call is a telephone call that is deliberately terminated by the caller before being answered by its intended recipient, in order to communicate a pre-agreed message without paying the cost of a call. For example, a group of friends may agree that two missed calls in succession means "I am running late". The practice is common in South Asia, the Philippines and Africa.
A stranger answering a call may disrupt a mutual agreement to convey a message. 
( z1 possible :ARG1 ( z2 disrupt :ARG0 ( z3 answer :ARG0 ( z4 stranger ) :ARG1 ( z5 call ) ) :ARG1 ( z6 agree :ARG0 ( z7 mutual ) :ARG1 ( z8 convey :ARG0 z4 :ARG1 ( z9 message ) ) ) ) )