The girls are helping teach Suzy how big girls roll or rather in her case don't roll. Suzy is hanging out in style while holding a SIT as the other girls ride their scooters around. Trainer Tracy is teaching her that just because other people move, doesn't mean she moves.
Adding distractions helps teach Suzy self control and that SIT means SIT no matter what is going on around her. The self control Suzy learns in this exercise can be applied to other situations too. She'll be better able to control her reactions in all types of public places and make her parents proud.
Good Job Suzy!