There is a rumour that taxi drivers in the UK are putting black ribbons on their aerials or bonnets to show support for jihad and the new caliphate.
I haven't found any online news media source for this. The original source I found is the Bournemouth English Defence League.
The advice, if you see these taxis, is to take photos and number plates and report them to the local council. Vlad Tepes also suggests asking the drivers why the ribbon is there.
It may seem trivial, but small things can have a much more profound effect than it may appear at first sight. We should take a lesson from the "zero tolerance" policy enacted by Republican Mayor Rudolph Giuliani in New York, who was in office from 1994 to 2001.
In an effort to eradicate crime from the city, his policy consisted in responding to any infraction, however insignificant. Graffiti and broken windows were among the things not to be tolerated any longer, as doing so was giving the offenders the wrong signal - a weak reaction from the authorities - and therefore encouraging them to go on to more serious offences.
"Zero tolerance" was highly effective. The reduction in crime in delinquency-ridden New York City during the 1990s was astonishing: “one of the most remarkable stories in the history of urban crime,” according to University of California law professor Franklin Zimring.
H/t to Vlad Tepes