When may medical staff come on, and when must I stop play for them?

SA Rugby's Protocol for Medical Personnel Entering the Field of Play:

• Qualified medical staff need your permission to enter the field. You can give it before the match (for example in the change room), or stop play and call them on. If they haven't been given permission beforehand, they must ask you before kick-off, and you should not unreasonably refuse.
• Medics who go on while play continues must not interfere with play or endanger players or themselves.
• Stop play if it moves within about 10 metres of medical staff treating an injured player.
• Your assistant referees should alert you if you are unsighted.

Apart from players and qualified medical staff, nobody may enter the playing area unless they show BokSmart certification.