Could one guest see or download another guest's photos? That's my biggest privacy worry with events.

No — the per-guest scoping prevents it. Each guest's access is limited to the photos matched to their own selfie, and that applies to downloads as much as viewing. A guest can't browse the album, can't search for other people, and can't buy or download photos they don't appear in. It's the feature that makes Snaptide usable for weddings at all — imagine the group-chat drama if any guest could pull everyone's photos. They can't, and that's by design, not by accident.