This form of disruption is perhaps the most difficult for attendees to do as most platforms have a number of settings that let you restrict permissions, letting you control who can share content – usually to a designated presenter role that you must promote attendees to.
It will take the form of attendees taking control of your slides and moving them around, or they may start sharing their own files or screens if you’ve not applied settings to stop them.
If an attendee shares their screen, you have no control over what they might display in your session, so knowing how to prevent this from happening or shutting it down if it does is important.