I would fully expect myself to have convinced myself that I am not experiencing hallucinations - particularly because hallucinations are often incredibly minor.

I am also very mindful about the dangers of telling people things that will alter how they interact with you.

Combining these I find it likely that there be a very high bar for knowing something like that - especially as it is likely a personal suspicion. Not all doctors qualify as over this bar.

Of course I would actively seek a doctor I was comfortable disclosing everything to, yet I understand a reluctance to do so.

Ironically, that point could be lost on those suffering from these sorts of symptoms - hallucinations, paranoia, etc.

It turns out that the people who need the most help might have a hard time telling doctors the truth about their symptoms for a variety of reasons. I think you're right that this would be better, but I think it would be really sad to avoid helping people just because they had problems with self-awareness and communication.

I might be wrong though. :)