This is not a new tactic. I have been told stories from the older generations about how the more fit Jews dressed in the orthodox clothing and walked where the religious were being attacked and harassed. When the people confronted them thinking they were the frail religious people they had harassed previously, they were in for a mighty surprise, a surprise I am sure they did not soon forget. The real noteworthy thing here is how big of a problem Anti Semitism is in Europe, and how fast it is rising.
"Dutch police are to use "decoy Jews", by dressing law enforcers in Jewish religious dress such as skullcaps, in an effort to catch anti-Semitic attackers.
Lodewijk Asscher, Amsterdam's mayor, has ordered the new decoy strategy to cut the number of verbal and physical attacks on Jews, amid fears that anti-Semitic "hate crime" is on the rise.
"Jews in at least six Amsterdam neighbourhoods often cannot cross the street wearing a skullcap without being insulted, spat at or even attacked," according to local reports."