I. I would advise the patient to prepare before playing their sport by warming up for a few minutes. I would advise to wear protective gear for their sport (if there is any) and to be careful to not push themselves too hard.
II. I would ask them if they have any history of injuries, if they feel pain anywhere and if they feel their body is ready to play the sport.
I think you're right with these advices. If I have a coach like you, I'm gonna do a lot of sport!
I really like the fact that you thought of suggesting using protective gear, as it might not always be obvious in some sports. I also agree with the fact that they should not try to go over the line and burn themselves out or risk multiple/recurring injuries.
This is good advice because it focuses on safety, preventing injuries, and making sure the patient listens to their body.