Jeff Saylor wrote:

So what's with the musical identifiers? A secret evil plot by the GPS
database providers?

Here's another interesting case, Drummond (Montana) Airport lost its three
letter identifier, DRU (or KDRU) recently. It is now M26. It will be
interesting to see where KDRU pops up next, I don't know of many cases where
an airport lost its 3 letter id.