Ensure you have a lost child / adults at risk procedure and that the organising team, security and venue are fully briefed.

Make sure there is a manned, clearly visible point for people to go to (and point out to their children in advance) in the event that they become lost or separated from the people they came with.

Indicate this on the site map

Consider supplying wristbands at the entrance, for children and adults at risk, with space for the carer to write down their mobile phone number.