Palm III and NAVMAN GPS question

Is it true that if you drive off the Streetfinder map, that the GPS will
turn itself off?  If that's true, then this product is of no use to me in
Canada correct?  Or is there other software that I could use.  I don't need
the maps, but I do want to record my position, direction, speed, and create
waypoints.

Sorry if this is a dumb question, I'm coming from the Garmin world...and
looking at this to be my backup GPS.

thx.