well put ryan, agree with you 100%...
but these hacks aren't invalid CSS. I think they're simply 'tweaks' that don't actually serve any purpose to the layout other than making the browser understand it and render it properly...

there's no harm in that, specially if it reassuers you that you will get the desired output...
a bug that hasn't yet affected you could at any time because, as you said, there are so many factors involved.