My lawnmower has open venting and I don’t have any problems with it . All I do is put 91 without ethanol in before I store it for the winter . I think it’s the alcohol not the air. And it gets stored in an open barn not an closed garage.Except there will still be some airflow, especially as the tank develops some vacuum as the engine sucks fuel out while running. If loops worked GM engineers would have used them over a charcoal can. The tank vents out with the engine off, and vents in while the engine runs. Closed venting does reduce fuel system issues by keeping moisture out. Even the fuel in the loops will still phase seperate and eventually contaminate the rest of the fuel and the varnish clogs the loops, blocking venting and starving the engine.
My tractor has open venting and the gas in it routinely phase seperates and eats the needle valve in the carb. Never had this issue in the Regal with intact Evap. Thankfully it only takes 5 minutes to replace the needle valve in the tractor but still annoying.