Adult only. Private by design.
What no reveal means

No reveal means the host ends the pairing for the night. It does not list who said no.
The short answer
On a key party, the host can send a no-reveal message when check-in is open and a full pairing is not possible. Your host invites friends. The host invites friends they'd love to have there. One private link per couple. The message does not name who said yes or no.
A guest who is checked in sees There will be no reveal tonight, then Thank you for joining. A guest who is not checked in sees the same title, then Thank you for your interest. A private no stays private.
Adult only. Private by design. You confirm you are 18 or older. The host still checks you in.
Guests do not see the yeses
The screen is a note, not a list. It does not say who matched, who declined, or who was left out. A one-sided yes stays hidden.
Sending the message does not check anyone in, and it does not release the street. The address switch is separate. After this message, the night is settled, and the address stays locked.
If you are still coming and the message has not been sent, Message host. That note is private. Do not ask the group chat who said no.
The other nights still reveal
All mutual-yes matches are revealed when the host runs that format. A no-reveal message is the key-party way to stop, not a second kind of match.
A key party that can pair everyone shows one Play Partner at the same time, after the host starts the reveal. A play party keeps matches hidden until the host reveals them. A speed date is short rounds, then yes or no.
FAQ
Does a play party have a no-reveal button?
No. A play party keeps matches hidden until the host reveals them. A speed date uses its own controls. The no-reveal button is on a key party.
When can the host send it?
During check-in, when a full pairing is not possible. On a couples-only key party, that is when no two couples have a mutual yes. On an individual key party, that is when someone would be left out. Allow group matches turns this button off.
What do guests see?
The title is There will be no reveal tonight. A checked-in guest then sees Thank you for joining. Someone who is not checked in sees Thank you for your interest. The screen does not list yeses or nos.
Does it show who said no?
No. A private no stays private. A one-sided yes stays hidden. The message is a note that the pairing will not happen.
When do matches show on the other nights?
All mutual-yes matches are revealed by the format. A key party that can pair the room shows one Play Partner at the same time, after the host starts the reveal. A play party keeps matches hidden until the host reveals them. A speed date is short rounds, then yes or no.