Originally Posted by masonsjax
A tiny pathway might not leak liquid under low pressure, perhaps not enough pressure to overcome surface tension of the beer, but could suck gas in while pouring, like a venturi effect. Maybe?
This is why I like to use 3/16" beer line and 1/4" hose barbs on everything, liquid and gas. It will never leak, even without clamps.
The Venturi effect is only applicable during fluid flow, so when he's pouring a beer like you mentioned. In his case the gas is appearing in his lines while the beer is static.