Coordinating the surprise in the family chat
A birthday frame is logistics, not marketing. Create it privately, set the campaign to unlisted, and paste the link only in the group that is in on the surprise. Ask everyone to switch their photo the morning of the birthday, or the night before if time zones are messy. The guest of honor should not see the link until the pictures are already up.
This is not a venue QR and not a ticketed list. There is no registration email. The entire distribution is one thread of aunts, cousins, and friends who will not download a party app for a Saturday.
