Regarding fuel tank vents there is a lot of history on this issue with certified aircraft.  Some of these aircraft now have sniffle valve vents in the fuel cap itself.  If a vent if plugged the vent will open and prevent the wing from collapsing.   FlightSafety showed me photos once of a Cessna Conquest wing completely collapsed from plugged vents with resulting structural damage.  Do any of the Lancair models have fuel caps that have integrated check valves?

Paul Miller
N357V Legacy