[beachwanderer]

No double or colloquial meaning there, just the location. - The thought behind that appears to be that the family did not identify with Charlottes "pamphlets" and as strolling down Unter den Linden was also showing ones social status (see and be seen) finding those works being advertised in public fell back on the family of the author as a group. They feared the gossip that was to follow ...