I have always assumed Z wore that outfit with a centered Cross-Hair stitched neatly into the center of the front overlay for the purpose of ego. I have always had a suspicion that, while I happily admit to having no evidence or grounds to show for it being anywhere near factual or true, Zodiac wore that costume with the cross-hair for His ego's curiosity in that the cross-hair by then was a known and published signature of the man police were calling 'Zodiac' and so if the victims were aware of events recently published in The Chronicle, The Times, and a number of other published newspapers then they would know, upon sighting His symbol, just who it actually was that was standing in front of them. If they did recognize or associate the symbol with Him as 'Zodiac',well then they'd also be aware that what He's just told them is a load of crap and He in certainly not a recent escapee from Deer lodge Prison in Montana nor, therefore you would likely assume, does He wish to steal your vehicle for purpose of fleeing to Mexico.
I always think that in the killers mind He was kind of giving these victims a chance, offering them the opportunity to recognize Him from that symbolic cross hair and as such, I would think He'd have to assume, would immediately try to get away whether He had a weapon pointed at them or not. If You are 99.9% certain that that man 10 feet away is, without doubt, a merciless and cold blooded serial killer who's responsible not for any vehicle thefts, nor prison escapes but several homicides then, I don't know about others but I Myself would be sprinting in the opposite direction gun pointed at Me or not . . . I'd know to stay there and comply = certain death so, what do You have to lose by attempting to escape?
Because the victims failed to recognise the Individual from the Clue slap bang in the middle of His chest then, well I can almost see Him rationalizing in His own warped mind anyway that these people are going to die and they are their own worst enemy because they are ignorant of who He is and He has just walked up and because He's wearing a symbol that The Zodiac has used to sign off in His recent letters to the Chronicle, letters that were subsequent published with that symbol. . . .How ignorant the victims are of such an important recent set of crimes and the most important person in the Bay Area at present, that being Himself as the individual responsible for having committed them,
Their Ignorance, He would likely believe, is both an insult to His own self-believed level of infamy and these people have not even bothered to take time to pay attenntion which, from His deflated ego's perspective and with a sense of rage and anger because He's not as infamous as He like to think can only be described as being: 'Deplorable at Best!!'