With a zero turn it works best to mow downhill. But it takes a pretty good hill to roll one regardless.
I ain't never worried rolling mine...but I've had to pull it out of a ditch , or the woods , a time or 3 ,
Because on hills , once they start sliding, downhill or side of hill...it's gone baby...ain't no stopping.
Uphill they are a beast , no problem.
Never have had front wheels off ground, of course mine is heavy commercial.
You seen my front yard...you don't go down that on a zero turn , skid marks 75 feet long looks bad.
what goes up must come down
Jim