Its about cooling the pak down a little. These tour paks are essentially a pressure sealed unit. So if I vent, i kill two birds with one stone.
If you really have no reason other than what you have stated, don't ruin your tourpack doing this. I don't care where you put the holes, water will find it's way in there. Again, like I mentioned in a previous post, if you insist on doing this, find some rubber plugs first, and cut the holes to fit the plugs tightly and then you can always seal it up from the inside for washing and rain. I'm not sure what year your bike is, but I'm guessing it's a 2010. I'm not sure if they fixed what many of us had as a problem on the 2009's. There is a very small hole in the front of the swingarm that is hidden behind the transmission and very difficult to even find, but water was getting in that little hole, forming rust, and dripping out at the belt guard area. Again, water will find it's way if you leave the holes open all the time. If you get the inside of your tourpack wet, and the liners as well, be prepared for a stinky tourpack, and eventually mold forming inside. Unless you are installing some high end stereo equipment that you are worried about overheating, forget about doing this altogether. If you have something that you need to keep cool, there is a Harley cooler for the saddlebags, and lots of coolers that will fit inside a tourpack.