Just sync watches and tell them they are unprofessional when they are 5 seconds early or late to brief. Don't accept either early or late.
And when they read back "report 5 miles" tell them that's the easiest way to spot an amateur and they will never do it again.
Another method to get them to do something they keep stuffing is ask them "Alright can you do [blah]". When they answer yes and don't do it they will kick themselves. Very effective.