The lesson in the latest death of a visitor to the United States - the 72-year-old British tourist Noel Fitzpatrick, who, it appears, mistakenly took the subway to one of Washington, DC's hell-holes and was shot to death - is that touring America's big, mean cities warrants special advice.
The horror of Mr Fitzpatrick's death in a darkened alleyway a few blocks from the White House follows the death of a German tourist in Miami. She hired a car, took a wrong turn off a highway and was bumped from behind by a car carrying two men. When she got out to examine the damage, she was beaten up and run over. Her sons, aged two and six, watched her die.
It is not only in the devastated and drug-ridden areas of America's cities that the hazards of America are encountered by the unschooled visitor. In the leafy suburbs of Baton Rouge, Louisiana, a 17-year-old Japanese exchange student was searching for a Halloween party and knocked at the door of the wrong house. The owner, surprised and fearing that the youth was a burglar, took up a .357 magnum pistol and shot him dead.
The Japanese government is now issuing booklets containing a basic survival vocabulary that includes the Japanese equivalents for 'freeze', 'duck' and 'back off'. Had the Japanese exchange student known these words, which the resident claimed he shouted, the boy might still be alive.
The British Foreign Office issues safety warnings to tourists travelling to Florida, but assumes that travellers appreciate the violence of American city life in general.
It is time for the British government to adapt a US State Department idea: For years it has issued 'travel advisories' to American citizens going abroad. These official documents are issued after an IRA bomb explosion in London, a kidnapping in Paris or a Mafia shootout in Milan. Watchful bureaucrats in the State Department's headquarters are trigger-happy with warnings - an especially bad bar brawl in Brixton is the kind of thing that can raise the alarm.
Warnings to British tourists should be posted by law in all British travel agencies and airports. A survival guide to American cities should be given to anyone buying tickets to New York, Washington, Miami, Detroit, Chicago and Los Angeles. It should be based on the street code well known to anyone who lives in these cities.
There are certain areas into which the average American does not stray. The area of Washington where Mr Fitzpatrick was killed is well known for prostitution and drugs, even though it is two blocks from one of the finest arterial avenues in the city. This leads through the District of Columbia, directly south to President Clinton's front door. The guide should shade dangerous areas. It is no good relying on glossy guidebooks to do this; it can only come from local knowledge.
In New York, Harlem is a tourist attraction. So is Columbia University. Both are in areas that are fine if you keep to the main streets, but the subway stops at 135th Street and 116th Street should not be used by out-of-towners toting cameras, money pouches and new sneakers. These items blink like a neon sign at a mugger. Dress like a bank clerk down on his luck.
If you ride the subway, adopt your 'subway look'. New Yorkers do, even schoolchildren. Whatever the weather, they look like a black cloud about to burst. Learn to walk like a killer. An ambling gait is like the smell of blood to an American street shark. The tourist who idly gazes at the top of a building, enjoying the architecture, has the look of a victim.
Beware the car-rental company that advertises itself with stickers in the car window. The German tourist in Miami was identified as a holidaymaker by the number plate on her car which had a tell-tale 'Z', indicating rental. With one eye on the victim and another on Florida's dollars 28bn tourist industry, the state's governor immediately banned new 'Z' cars and asked car- rental companies to remove the 659,000 'Z' plates already attached to these bright, new cars. The governor did not order the removal of promotional material from licence plates and bumper stickers, however.
Always drive with the car doors locked and avoid stopping at traffic lights. Sound crazy? Los Angeles residents try to cruise at exactly the right speed to get all the green lights in bad areas.
Included in the guide should be the latest crime statistics. Actually murders are slightly down this year, but the number of handguns siezed by police is up - 12,497 last year. They were found all over the place - in a baby's pram, a hospital examination room and a portable lavatory.
A safe distance should be kept from unidentified packages in public places: a way of life for Britons facing the IRA threat.
Finally, the guide should give a picture of what the future could look like. Cities are emptying of shops, and residents are spilling out into the for-the-moment safer suburbs at an increasing rate. They call it the 'Edge City Phenomenon'. Gun laws are tightening in some states, breaking traditional barriers in the relationship between the demand for public safety and the right to bear arms. New Jersey and Connecticut followed California's lead in banning assault weapons, a defeat for the gun lobby led by the National Rifle Association. But the NRA's membership is now a record 3.2 million and growing.
These are facts and figures, not opinions. The Foreign Office should be able to publish them without upsetting the special relationship between Britain and America. It would be irresponsible not to do so.