Safety first, is the justification for using KFC to coax five young people off a youth justice facility roof.

The group spent almost 24 hours on top of Te Puna Wai o Tuhinapo in Rolleston near Christchurch last Saturday.

Former police negotiator Lance Burdett says negotiators see people as people, not for what they've done.

"The idea is to de-escalate as quickly as possible. Certainly if people are up on the roof, there's a risk- so how can we get them out of that situation safely."

Burdett adds the decision is also usually made through command chains, not by somebody not emotionally involved.

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