I've never left the plug out but when I was in high school my friend, his girlfriend and I went fishing with my Dads boat. My dad is real particular about things and when water started coming in the back I started to panic a little. When we realized that the aerator pump had broke off and the water was coming through it I went back to the ramp. When we got home I showed my dad and he asked, "Why didn't you just stick a rag in it to plug it and keep fishing?". Hmm... Good question, maybe because I wasn't wanting to get a lecture when I got home! I currently have 3 plugs in my boat. I always keep it unplugged when not on the water, that way I have a routine of taking off the transom straps, transom saver, putting the plug in, and opening the gas vent. If I know I take the plug out, I will never second guess if it's in or not. Now my luck I'll sink my boat tomorrow by forgetting the plug.

On a related note, the first time i saw my dad pull the plug while a boat was on plane I thought he had lost his mind. I was about 7 or 8 and I started to panic! Nice trick to keep in mind though.