If there's a health issue with a kid, I send the arbitrator an email and ask for 7 more days. No formal "motion for continuance pursuant to local rule 8.9(c)(3)(f)."
Lastly, I agree that this a tool. I like to think of arbitration, in this context, as the best customer service tool out there. Remember back when the hack was that you send a letter to the office of the president and that got you a competent response? Arbitration is like that on steroids.