And once you file a complaint against the cops for violence, you end up targeted. Either for harrassment (as happened to me) or for frivolous counter-suits ("Widerstand",happened to a couple of friends).

Filing complaints against police is pretty much pointless, as evidenced by the numbers (of 2138 cases, only 33 ended up in court, see https://correctiv.org/blog/2016/02/12/polizeigewalt-zahlen-f...) or by the sheer time scale. The poor old man who had his eyes shot out by a water cannon at S21 had to wait SIX YEARS for an offer of compensation (http://www.sueddeutsche.de/politik/umstrittene-polizeiaktion...).

And even if a state like Berlin requires numbered cops, if there are supporting units from other states these do NOT have to carry numbers. Witnessed this first hand when beaten up in Berlin by cops from Dresden.