My lawn has a gentle 10 degree slope that tapers into a 15 18 degree hill on 2 sides. One day, I was happily mowing along on my new Hustler Mini Fastrak 36 ZTR and was on the edge of this slope when all of a sudden, the front caster wheels unexpectedly and without warning swung down towards the steeper hillside even though my steering levers were pointed straight ahead. So now I was hanging on the steep hill with the front casters pointing downwards on the 18 degree slope. When I tried to drive in reverse, the back tires just kept turning with no traction at all. The only thing that was keeping me from rolling downwards was the ZTRs integrated brakes and the pressure from the dual EZT hydros. So I gingerly stepped out of the seat, and when I released the brakes and the two hydro levers behind, the Hustler took off without me and ended up in the ditch about 30 feet below. Luckily, it did not roll over, presumably because of its low center of gravity. Other than avoiding mowing that section of the lawn, which would defeat the purpose of my buying this ZTR, is there any way I can keep the front casters from swinging in an unintended direction? I seem to recall that a competing model, the Ariens Mini Zoom 1740, has lockable front casters, and perhaps that would help me avoid this near-disaster. Any equipment mods, or change in operating technique, that would help? Thanks for any suggestions.