Both Transportation and CoupledTransportation have local versions of the base G4VProcess::SetVerboseLevel() function, and their own local fVerboseLevel data members. Because the base function is not virtual, these local versions (and especially the local data members) make it impossible to set verbosity using the UI command /process/setVerbose. What's more, because the Transportation process is instantiated not by the user, but by the base physics list classes, there is no simple way for user applications to change the verbosity of Transportation.
Thanks for reporting this. Now fixed in tag transport-V10-03-02 which will be included in the next release.