Before passing judgement, you might ask for clarification or additional information.
Page 46 of the HotSpring Owner's Manual states:
"For maximum protection against freeze damage to your spa, Watkins Manufacturing Corporation recommends contacting your HotSpring dealer to schedule an in-home Propylene glycol (anti-freeze) Winterizing Service plan."
A copy of these instructions were provided to me by my dealer as part of my start-up package.
For more information on how to properly winterize a spa, see: