On 06/01/2012 10:57, Paul Rigg wrote:
I think his point was, and I think he is right, that the DDR authorities
allowed anyone to cross the wall who was either not one of their own
nationals or a national of another country (ie the Eastern Block) with
whom they had an agreement to stop travel.

Did Soviet officers often cross into West Berlin for the day?

The West German authorities did not check entries to West Berlin from
East Berlin, presumably because of the four powers agreement which said
that West Berlin was made up of British, American and French Sectors.

West Berlin was technically not a part of the Bundesrepublik, IIRC,
although its citizens did have West German passports.