Event attendees expect the information they provide organisers is protected and shared only when they give permission. This may be a requirement by legislation in some jurisdictions that protects the individual and use of data an organiser obtains. The GDPR introduced in 2018 is an example that mandates this.
At the event, attendees will be provided with a Smart Badge. It's like an electronic version of a business card. It is important attendees understand they are empowered to share information with others or not. Good practice involves informing attendees during the pre-event registration process about the use of Smart Badges and educating them on the steps you take to protect them.
It is important as an event organiser you consult with your legal representative to ensure you comply with any necessary legislation. An example of copy that could be included in event registration Terms and Conditions is provided in this article. It is provided with no warranties and will require your own legal representatives to review it for suitability to your situation.