I was not interpreting the rule in an absolute sense at all. I would never say the rule means that regular conversations triggered within the game, even if it starts only because Garrett crosses an invisible line, to be a bust. That would be in an absolute sense. I was quoting that statement from the rules because it specifies situations that goes beyond normal comments that indicate AIs' reactions to something you do, something beyond simply being seen or heard, but still triggering some kind of alert. I took loot, that initiated a response (scripted or not) from the enemy. The result of that script is for him to say "someone must have stolen that" is to me an alert of some kind.
The part in bold that you reference "No Alerts of any kind from any AI or Device" doesn't refer to the level 0 or 1 states that it seems to me you on the other hand are taking as an absolute. It is instead talking about "alerts of any kind" as the heading, so that is the context, not the state levels you mention. Then it goes on to list "first alerts" as an example of what that could be, but then it also lists other examples of what such alerts could be. So to me, "All AI and devices must remain in their normal state and not react to anything you do or initiate in the game" goes beyond a normal first alert state to include other scenarios that could also cause alerts.