I really think it should go toddler, moving obstacle, THEN preschooler! :-)
My LO is under my feet, on the table, goosing me, a fall to crawl so I'm taking giant steps to not fall myself, grabbing my leg, falling hard at the playground, on and on. Just a ball of insatiable energy, bouncing around endlessly around me and any other person or object without a single care. If the isn't a moving obstacle I don't know what is!