As long as you always remove the drain plugs when not sailing, you should be fine.
If the hulls are well sealed, you may still occasionally get a woosh of air from the hull when pulling the plugs, even if the vent tubes are working. Consider for example, you're sailing on a hot summer day but on a body of water that's relatively cool. While sailing, the air in the hull is cooled by the surrounding water to say 70 degrees. When you remove the boat from the water, the outside air (say at 90 degrees) is going to cause the air in the hull to expand quickly and build up some pressure before it can fully vent through the small, 1/8" vent hole. So the air is likely venting, but this doesn't happen instantaneously when there's a large temperature swing.
This baffled me for a while because I would come in off the water (on a hot day) and pull the drain plug and I'd get that woosh of air, but I'd also get some water draining out and wonder how the heck the boat could leak water but be air tight.