Water all over beach, then strange male couples stealth run, not announced anywhere

On my way back the beach was suddenly populated. Male couples, all healthy looking, not young, none under 30 or so, none older than 55 or so, not in packs, just spaced couples, no race numbers visible but similarity of attire (backpacks required), wearing mainly black or blue. Men from Cayucos taking over Morro Bay from the old folks? No, they did not advance inland. In Marin County I would have thought gay work-out buddies or partners. Who knows?