What are wild lines, and why are they not present in theatrical productions?

A wild line is dialogue that is recorded on location, but not at the same time as it's complimentary footage. Some times when filming on location, certain dialogue or lines are not recorded properly for one reason or another (unexpected loud ambient noise).

wild lines are lines that actors repeat when they weren't clear enough to be heard the first time. Theatrical productions are live, and you cannot go back and change what has already been done.