I just don't get all the hang-ups in regards 'battery venting'. If a cell catastrophically fails then half a dozen wee holes will not be of much help. Unless it's to direct the jets of flame ?
Mooch did an excellent interview (find it yourself, i did) regarding the whole issue of batteries venting and (very, very rare) total failure of a cell. In the event of venting due to over stressed batteries the pressure build up in a mod is minimal and will escape through any seam.
Scare stories are driving the 'vent hole' debates - maybe we should change the question to 'where are the cooling points for the board' - probably more relevant ? .....
Sorry about the rant. I was just venting.