FRA has been doing this for a long time. I used to travel regularly on LH from NUE via FRA to BHX. Because the UK isn't a signatory to Schengen, flight to UK used to wind up boarding next to departures for such unsavoury destinations as Israel - and I wondered if this over to top security wasn't in some way due to the "company" which we were forced to keep, in the way of the destinations of adjacent aircraft.
Anyway, being outside Schengen makes arriving and departing a more longwinded process. How about starting a petition get get our government to sign up - soon! I for one am fed up being treated as a second class citizen within the EU.