East Germany c. 1970? Nope, UK 2010.

[tank slapper]

Remember those posters on bus stops telling people to phone up and report 'suspicious' people, like those going about their normal business? Well, they obviously didn't do the trick so they have added radio adverts now:

http://www.youtube.com/watch?v=GIAFHjL3ZMg

[tank slapper]

It appears that some people complained about these adverts, and they have subsequently been banned as they are considered offensive. About time too.

http://www.bbc.co.uk/news/uk-10929203