Jack Shafer has a terrific piece debunking the myth (recently seen in Newsweek) that Vietnam vets were routinely spit on:
In researching the book, Lembcke found no news accounts or even claims from the late 1960s or early 1970s of vets getting spat at. He did, however, uncovered ample news stories about anti-war protesters receiving the saliva shower from anti-anti-war types.
Then, starting around 1980, members of the Vietnam War generation began sharing the tales, which Lembcke calls “urban myths.” As with most urban myths, the details of the spat-upon vets vary slightly from telling to telling, while the basic story remains the same. The protester almost always ambushes the soldier in an airport (not uncommonly the San Francisco airport), after he’s just flown back to the states from Asia. The soiled soldier either slinks away or does nothing.