I've got to agree with genixia here.
If you own the garmin map software then presumably you can use [within reason] for your Empeg [this is like ripping mp3s of CDs you own].
If you obtain the empeg version of the data without buying the map - then thats wrong [thats like downloading the mp3s from Napster etc].
any license restrictions you sign when you use the software are probably there as a requirement of whomeever Garmin license the base data off of.

In the worst case, if you had to buy a Garmin GPS to be able to legally use the map data on your empeg then I doubt too many folks would complain - that would be the cheapest option for many people.

I do also agree with your comments about avoiding "Imperial entanglements", BUT I suspect there isn't a set of usable GPS/map data in the world that is free of such entanglements though so its kind of like wishing gravity would vanish.