I could see it if no one else could press play for you and you have to dash to the furthest point on the ice, but otherwise, 10 seconds is waaaay too long. Makes those skaters waiting for a runthrough grumble about your inconsideration.
I assume we're discussing lead-in time for pressing the play button for oneself. If someone else plays the music the answer would be 0 second.
Really, between 10 and 5 we are just talking about 5 seconds differential. Maybe it's East coast vs Midwest?
Honestly, our skaters are accustomed to 30+ seconds wait in their starting pose when the monitor runs music... excellent use of precious lesson time, I know.
Getting out of the hockey box takes some time, I normally wait less than 2 seconds in my starting pose. And if I have to play music myself, it means no monitor and light session, so people are less likely to grumble.