H4i spill guard - useless?

Hello,

I just upgraded from the H3i to the H4i humidifier for my Resmed S8. The H4i adds a "spill guard" that fits into the semi-circular cavity at the top of the water chamber. Is this extra part really necessary to use for proper operation? The manual barely mentions the darn thing and I can't see how it protects against any spills. I tried the humidifier with and without the spill guard and saw no obvious difference in operation, humidifier performance, comfort. Since it is just an extra part to clean and replace, I was wondering if anyone new more about it and whether it really adds anything other than extra cleaning.

Thanks,
Sgt Wilko

Resmed recommends removing the tank to refill it, or for moving the unit. If you do that, it doesn't matter if you use the "Single spill guard designed to prevent spilling and splashing during the filling of the H4i water chamber". I have the H4 also, and it does't seem to make a difference, unless perhaps you move the unit with water in it. You don't want water getting into the electronics.