Mystery gas leak solved!! Thanks, guys. You were right. It is an “O” ring problem. Tonight I removed the cap and discovered that the “O” ring was missing . . . as in no “O” ring - zip - nada. As per Paint’s suggestion, I checked the parts manual and there is definitely supposed to be an “O” ring between the tank and the filler cap. But it’s not there! I'll pick one up tomorrow and that should solve the problem. Thanks again!
So if your Sport Classis/Paul Smart is not leaking don’t worry. It probably won’t leak.