Here's my non-expert opinion:

Charlotte may have some Sabals, but my guess is the bulk of them are in palm enthusiasts' yards like Ken's. I just don't think there are enough Sabals in the area to support the Sabal moth or any Sabal-specific pests.

When the lethal yellowing thing was going off in Florida, I remember thinking that if the pathogen killed all the Sabals in Florida, and the contiguous populations of Sabals in the Gulf states, up through the Carolinas, the palm nuts growing them outside their contiguous range will be the saviors of the genus. In theory, disjunct populations ought to be relatively safe from Sabal-specific contagions and insect pests.

I have a Birmingham & a Palmetto - both in-ground since 2008ish - and I feel pretty confident that the only threat they face are the winters here. How is a palm moth or a lethal disease gonna find them in Delaware? And in my mind, Charlotte would be nearly as safe.