Write down the name, address and phone number of your hotel. Have each child carry a copy.
Most hotels have business cards or matchbooks.
Of course, if matchbooks are used, remove the matches before giving them to children. Explain the local police uniforms and where they may be able to find help if they become separated. Give them coins to use pay phones and show them how to operate them. Let them practice. Establish rendezvous points in the event someone gets separated.