To quote: "The skirting issue is a real hotbed...in order to get insurance coverage for your unit the insurance company demands that it be skirted and that you provide a photo of the unit.....the apparent reasoning for that is to keep wildlife out from under it and to stop a hot firecoal ember from starting a fire underneath"
I am sure that skirting would keep out larger critters, err wildlife. After seeing what mice can do and how you rarely can find their entrance hole, I am not sure in my ole mind that skirting would keep them nasty monsters out!
My 2 cents that ain't worth 2 cents.
I have someone I am gonna ask about this, not sure when I will see them tho. They own a lot here in the Valley and drag their unit home every spring, much the same as Bill and Ann. I think their answer will be close to Bill and Ann's. That thinking and a buck fifty MIGHT get ya a cup of coffee.