When you get some fuel blowing into the tank area through the line holes it is more of a little mist that will show up on the epoxy sealed wood or exposed fuel tank. If you find heavy oil/fuel under the tank then like John mentioned, you probably have a little leak.
If you have a leak it should be showing up as bubbles in the line like Dave mentioned.
If you are at idle and see fuel dripping on the ground you really want to pull the cowl and look to see where it is coming from. Ihave had pump regulators leaking and didn't notice it until Ispotted the drip.