My plane has a Rotax 4 cyl, 4 stroke with a dry sump and the tank is foward and level with the engine. We turn the engine if not used for a few days because modern oils are such low viscosity that the oil siphons into the engine thru the oil pump in some (crank) positions if allowed to stand for a good few days.
The pressure generated in the crankcase, even with just turning over, is enough to push oil back into the tank. The tank level rises to normal. If you check the oil without doing this you can easily overfill.