you will recall that the caller seemed to backpedal in his description from a borderline deranged man to someone who is just hyperactive.
I recall the caller stating more than once that Scott was having trouble walking and was acting erratically. He may have later used the term hyperactive as well at some point in the conversation, but I don't recall anything that could be construed as "backpedaling" from his repeated assertion that Scott was acting erratically.
Also, as far as I know, Erik was not asked verbatim to leave the premises.
The police didn't shoot him for trespassing, they shot him because according to the police and the witnesses he pulled out his gun when confronted.
The police didn't come to the store because of a trespass call, they came to the store in response to store security calling about a man with a gun acting erratically.
I believe you are probably right about them not asking him directly to leave. They were, in fact, evacuating the store at the time that Scott finally decided to leave which indicates that they probably figured he was going to stay and that it would be better to get the customers out instead. But, as pointed out above, since neither the call nor the shooting were over trespassing, I don't think whether or not he was asked to leave is particularly relevant.
The call was based on inflammatory information and the impression that he was unstable was given to the officers responding to the call.
The call was based on the direct observations of the caller who was watching Scott during most of the phone conversation. The impression of the caller, based on what he saw, was definitely that Scott was unstable. So if the information was inflammatory, it was because the caller, based on his direct observations of Scott's actions felt they were inflammatory. And if the caller gave the impression that Scott was unstable (and I believe he did give that impression) it was because the caller felt that Scott's actions were unstable.
It can seem disconcerting if you aren't used to it as he's kind of jittery and twitchy.
I don't believe that anyone could, with a straight face, make the claim that it is reasonable to equate "jittery and twitchy" with ripping open unpurchased packages in a store, having difficulty walking, claiming to be a Green Beret, being unable to fill out a simple form, and pulling out a gun when confronted by police officers.