This is why a 100 series Cessna parked with the left wing low, and full tanks will dribble out the vent. It'll keep dribbling, until the fuel level goes below the tank vent (many liters) so best not leave the plane that way.
My 'after landing' check in a 172 is to turn the fuel to 'R' tank and leave it that way until starting again, even if the a/c is going to sit in an allegedly level hangar.
With a 150, which only has a 'both' or 'off' option, if you fill to full then leave it in the hangar, best put a dustbin under the behind-the-strut vent. Personally, I leave the tanks on a 150 no more than 2/3 full, then top off immediately before flying if I really need full tanks.
TOO