The board I'm on used to only allow in-person votes for various good reasons--though we've since changed this for equally good reasons. I remember there was some contentious episode or other where there was an argument along the lines of that, given the importance and disagreement on this important issue, surely we want to allow phone votes/proxies given "Joe" has some family stuff going on and can't make the meeting (hypothetical scenario). But the bylaws were very clear that only in-person votes counted so it was hard for anyone to make the case that this situation warranted bending the rules.