yep...It will immediately get water logged and break extremely easily, not to mention get really heavy. Be careful handling the board like that too, it's easy to get splinters.
really? I usually go through 3-4 boards a season and everytime I get a hole in it, it starts to get water logged and eventually breaks. I guess if it's still going strong it would be ok on the rails. You might consider putting some kind of sealant on it so it slides better. It looks like it'd be really sticky the way it is.