Saying "someone lost $500k" definitely implies one person. 10,000 people losing $50 isn't noteworthy. And someone at the door? If you see 3 people, you don't

Saying "someone lost $500k" definitely implies one person. 10,000 people losing $50 isn't noteworthy. And someone at the door? If you see 3 people, you don't say someone. You'd only say someone if you're expecting it to be one person (which it usually is knocking at a door).