Are you allowed to cherry pick if you're not champ?

This is something I remember Sergio Martinez said in the build up to the Chavez Jr fight. He said that Chavez kept ducking him for a long time, Chavez's team said they did not want to fight Martinez yet until Chavez got better and had more experience. Martinez said if Chavez was just a contender then he could keep cherry picking opponents but since he had a championship belt, he had an obligation to fight the best and not duck anyone. Which makes sense. So do you guys think fighters are allowed to "duck" or "cherry pick opponents" if they are not champions? Like if they are trying to get better before facing a real threat.