Can fuel sloshing in the tanks cause a stall? Cargo planes secure their load meticulously and if it breaks loose, the result is sometimes catastrophic. However, how do you prevent fuel sloshing inside the tanks and causing the same problems as loose cargo?
There are dividers (baffles) in the fuel tank precisely to stop the sloshing. They are just large plates that will stop the fuel from flowing across.

High maneuver jets will use bladder tanks (so no air is in the tank with the fuel) as a way to contain the fuel.