Any finishing, piping, attaching of flowers and sprinklings of glitter are done until your cake is completed and looking fabulous. I take a photo and let the venue know any requests or non-edible parts they might need to be made aware of.
Often you want your evening guests to see the cake and do the cake cutting and first dance around the same time. After this, the venue takes away your cake and cuts it up for everyone to enjoy alongside the evening buffet.
I hope you love your cake as much as I loved making it.