If it was such a traumatic thing for Harvey to be "accosted" by Knight, yeah, I think he might have reacted to move his arm away, but he didn't, so I don't think it was such a big deal to him what Knight did until he mentioned it to his attorney uncle who had earlier written a derogatory piece against Knight...he had a bone to pick with him. His uncle contacted the press, knowing all hell would then break loose. The Harvey kid later said he regretted ever mentioning the incident. It caused him to feel compelled to transfer to another school afterwards. I really don't think Knight's response to Harvey was that big of deal to the kid at the time. It just morphed into something greater because it involved a larger than life figure with the name of Bob Knight and one of his adversaries relishing in the attention he got for blowing the whistle on him.
I've never grabbed another adult to get their attention so I don't know how they would react. It would probably depend on how much the person either liked or hated me.
In PR, all the IU players said it didn't happen the way de Silva claimed it did. All Knight did was point his finger in his face (not poking him in the eye while doing so!), certainly not the assault claimed by the police officer in a country steeped in social unrest at the time where every American was considered an "ugly American". There was real tension between the US and PR at the time of these Pan American games. Our starting guard, Kyle Macy, had his jaw broken by an opposing player during one of the games. For Christ's sake, now THAT was a rough foul of malicious intent but no one remembers that, only that Knight "beat up" a police officer.