Rule from the 60's: Don't trust the new guy urging others into a confrontation, particularly if they were more interested in that than the beautiful women who was trying to flirt with them. During the civil rights demonstration and more so with the protests against the Vietnam war, you often had active duty military trying to pass as college students or as Vietnam vets.

We know how quickly we spot most trolls, et al here. It similar back then. Even by claiming to be a student at a school 500-1000 miles away and are visiting some friends here, you would not pass inspection for long, particularly if you haven't attended college anywhere. But passing as a college student was far easier than passing as a Vietnam vet. Far too many details, unit numbers, forms, equipment, slang, people, pranks, and on and on.

Sometimes they were so obvious. Several forgot to remove the base tags (decal) from their car.