Arguments about screen-readers seem to be mostly based on superstition or wishful thinking. Some seem to believe that screen readers are actually the fabled and elusive semantic browser which understands the subtle semantic differences between UL, OL and DL, but on the other hand is stupid enough to just crash upon encountering a TABLE without a TH.

This might be the case, but it would be really interesting to hear something about it from someone who actually have real-world experience with them.