Just as a plane had left the gate at the Baltimore Airport for a flight to Chicago, one passenger saw a "Middle Eastern looking" woman looking at a video that appeared to be associated with the Islamic State. The alert passenger told an attendant, the plane returned to the gate, police arrived and led off  three men, a woman and a baby. A search of baggage and belongings found nothing, and the people were released without charges.
The story suggests that dark skinned passengers should avoid looking at material in Arabic, Hebrew, or Armenian. Most Americans cannot tell the difference, and the results could be unpleasant.
There have been police actions in response to alarms at a football stadium in Germany, an airport in Denmark, and an underground station in London. Several Air France flights have made emergency landings mid-flight, uneventful other than being associated with a security warning.
A police action in a Paris suburb is said to have prevented another catastrophe, as well as resulting in the deaths of several Arabs who participated in an exchange of fire, and a passerby caught in the wrong place.
For some years now, Israelis have been advised to avoid speaking Hebrew on travels elsewhere. For many, that would mean not speaking.
Pull into yourselves when traveling in the land of some other tribe. Suspicions are intense. What some people call traditional justice, other people call vigilantism. Lynching does not only mean hanging someone from a tree. It is also used for cases where a crowd beats an unfortunate to death, occasionally without justification.
A month ago an Eritrean was shot by a security guard in the Beer Sheva bus station during the pursuit of a knife wielding Arab. It was later determined that the Eritrean would have died as an innocent who should not have been shot, but he was also beaten and kicked by several people in the terminal, including an off-duty prison guard.
Years ago, when I was working in Kenya, it was common for thieves to be chased and beaten to death, in what the major English language newspaper justified as traditional justice, enacted against poor people had robbed other poorer people. The call "stop the thief" would recruit just about everybody, who would chase after some young man running like hell for his life. I once saw an English speaking European leading such a crowd. There were stories of individuals thought to be innocent, who didn't live to convince anyone of it.
I've gotten onto the lists of several African American activists who send me reports of police brutality and murder. They usually come with pictures or videos, thanks to the universal spread of smartphones. The material looks ghastly, but who knows about the editing. The intensity of the verbiage should make anyone who was more than 50 meters from the event suspicious of fabrication or exaggeration. We know that the professionalism of local policing in the US is often at a low level, and that local and state politicians, as well as elected judges and impaneled juries are unreliable in what they say and decide about activities that arouse  racial or ethnic sensitivities. African Americans may be guilty of something, including resisting arrest.
Israelis are familiar with parallel routines. Arabs shot and killed in the videoed act of violence are described by family members as nice kids, killed by police and military murderers. The President of the Palestinian Authority and others in prominent positions echo the charges. Streets and other public sites are named after the latest individuals killed for the sake of Palestine. 
Injustice does happen. We'd be blind to deny it. But so does incitement. We'd be blind to deny that, as well.
Israeli Jews are lucky. We live as a majority in an ethnic society. If we speak decent Hebrew and look Jewish, we're not bothered by the police as we walk on the street. We go quickly through security checks at the entrances to banks, supermarkets, universities, hospitals, and at Israel's airport.
We're less lucky when times are tense. Then we may choose to stay at home, perhaps in bed or under the bed, or walk with whatever we can carry as our weapon, and alert to whoever is close to us on the sidewalk.
Those of us who are sensitive, as opposed to those always alert to an opportunity for vengeance or traditional justice, may worry about our Arab friends and acquaintances, or Jews who look like they may be Arabs. Except for those of us who have acquired a European ancestor over the centuries, there aren't clear physical distinctions between Israeli Jews and Israeli Arabs/Palestinians, leaving aside those of each community who dress as their religion dictates.
We're not only aroused to worry by the recent series of Islamic State atrocities (including that against our mutual enemy Hezbollah), but by the Arab response to Israel's move against the radical Islamic Movement. That has produced widespread assertions that it is a social movement and unjustly accused of radicalism. We've seen and heard films of enraged incitement about the Temple Mount and its minions spitting and yelling against Jews daring to visit the Mount. The defense is about as convincing as the claim that child killers are good kids.
Israeli Arabs proclaimed a general strike for Thursday. Friday will be exciting at the mosques, and after prayer. Police should expect to be busy. It may be a good time to stay under the bed.