Personal details in news sheet/website

In the UCAN guidance issued ahead of GDPR in section step 4 point 4 (on page 8) it said "stop publishing details of individuals....channel comms through the office." What about the situation where an individual is selling tickets for an event and wants their phone number included so people can contact them (without looking up in ChurchSuite or paper directory). Any wisdom on this gratefully received! Thanks Chris Harris.