No, I'm used to being addressed that way often, and in person people just tend to drop the "Mpls".

On the other hand, I sometimes feel really awkward addressing other FT'ers by their handles, e.g. at ELP it didn't bug me to address you as Canarsie (because I sort of "knew" you) but I felt really out-of-place addressing a 60-ish couple in-person as Hunki and Punki.

I think it depends on ones familiarity with the people involved, both on-line & off, and on how close the FT handles are to being appropriate as real names.