I always ask for a copy of that appraisal - maybe there is some information that I don't know about. Only once have I gotten the appraisal. I think the rest had all lied, and were hoping I'd buy the lie and pump up the value.
I had one a few months ago that did give me the appraisal, and it was $30,000 above optimistic. I had comparables on the same block, and 2 active listings a few doors down for far less, that were not selling. Previous appraiser had used superior constructed homes in a higher priced subdivision. So I told the LO that I did not do a full fledged review of the previous appraisal, and did not know if the comparables used were the best that were available at the time, but that given the information that is available now, I cannot conclude any higher value without getting us both into trouble - "and we don't want that, do we?" That LO then said, "well, you can't win 'em all". He still orders from me.