Well, there should have been a few ounces of water in the P trap and loose fittings could distribute it. It is the most likely culprit as the water pump was not on while you were traveling so only residual pressure.
The flashlight check while the water system is under pressure is your friend.
Old (usually dirty) Nissan Titan
Old (enhanced with "male pattern baldness") Sovereign
Young, lovely bride
Goofy dog, dismissive cat