It was always called "Practice" when I was growing up. Now that I am older, I don't care what they call it - for me it's most definitely "warm-up"!! ;-)
What difference does it make what they call it?
Since they often say, after this session is over, "Begin bowling for score", think of the previous 10 minutes as "bowling, not for score". What you do with it is your business.
I also use it to warm-up, get the feel, get my slide right, etc. I know when I'm "warmed-up"; then I begin to try to learn how the oilman screwed up the pattern this week or how many screaming 10 year olds threw plastic/urethane balls down the lane between the time the lanes were oiled and the time we're bowling.