FYI: there are several EMS helicopter operators along the east coast that fly under a "Life Net" banner and use call-signs (not reg) of "LN" to provide special handling. I'll bet for most of the ATC people you talk to this is the first time a LN registered aircraft crossed their airspace.but ATC keeps asking if we are a medivac chopper, turns out that our LN tail reg is used in the US for medivac choppers.