User blog comment:KidVegeta/Canonicity/@comment-3097771-20101130081512

(2)

World's Strongest is non canon, due to it's timeline overlooking. This movie could not have taken place, as Piccolo would be dead at the time (Which would have to be after Vegeta Saga) and everyone else would be on Namek. Timeline errors are severe canon breaking material, and can not be overlooked.

Final Ruling: Not canon