gregscheetah wrote:
Since direct can only be given under radar control (IFR GPS or
otherwise) ....


I am not sure where everyone is getting this information. Maybe it is
a 'rule' but I have often been given direct routes when out of ATC
radar and, for a while, out of ATC communications.

The "rule" is that direct routes initiated by ATC are limited to the
service volume of VOR (or rarely, NDBs) and the controller can assure
that MIAs will not be violated.

When the pilot makes the request, though, let the buyer beware.