This may be as designed, but it's not how most systems do it (in my experience). Both my VW OEM unit and my JVC would scan the entire frequency band (not even just preset stations) for traffic announcements - I know this because I'd get things like BBC Leicester or something popping up when I drove down the M1, and I sure didn't have that as a preset!

I think yoour description is inaccurate. What those headunits do is actually this:

1. Monitor the current station for TA flag.
2. If the reception of the current station gets to bad, check its alternate frequencies. If one works, set the current station to that and start at (1) again.
3. If no alternative frequency for the current station works, scan the whole band for the best station that supports TA. Set the current station to it and restart at (1).
4. If no alternate station supports TA, tell the user about it. My old VW radio had a very unnerving beep to do so.
   

I really hope that the empeg will work in the same way.

cu,
sven