USMS sanctions require all participants to be current USMS members (or one-event members, if applicable). USMS recognition allows USMS member's results to count as official times, even if not all participants are members. USMS insurance covers sanctioned events, but not recognized.
Any event that is not applying for a USMS sanction/recognition. Examples of these events: a pool or open water clinic, a kick for time event, a fun relay event or an event sanctioned by another governing body.