Nobody announces it. People just start drifting outside, coats half on, and then the first shell goes up and every single face in the garden tilts back at the same moment.
A display choreographed to your music, built to the size of the venue and the mood of the night. Low noise options where neighbours, livestock or nervous guests are a factor, and indoor close proximity effects if you want sparks behind a first dance rather than a full show outside.
It costs you five minutes and it is the last thing your guests see. Which, as it turns out, is the thing they end up remembering.