Yes, private pool party in HOA neighborhood, subject to HOA’s rules & guests needed permission to attend.
Someone put it out on twitter & people crashed the event, jumping the fence.
DJ had setup nearby & was playing rap music; this (plus the fencejumpers) was one of the things that prompted the calls to the cops.
Check FR keyword ‘poolpartycrashers’ for more info on this.
I wonder if the security guard was hired by the party organizer or the HOA.