I think they are ordered by fans and brought to the venue by florists in most cases. The fans were obviously expecting him to skate to his SP at PIW by looking at the colors they chose
I'm not sure if it happens at other shows, but at PIW, it seems to be the custom for the skaters to sign on the cards attached to the flowers to show acknowledgment and gratitude towards the fans.
Great tradition! Definitely a "warm, fuzzy" for the skaters. It's kind of like giving them a hug. Very cool...I noticed they were lavender. I'm sure the fans thought the flowers would match his new purple deep V. For some reason it made me nervous today to see how close everyone is to him. Be safe Shoma!