The success rate for pre forclosure is low for an experienced agent. Then the time and energy put out for a deal that will likely not work anyways its a wasted effort.
Like super said, if you want a listing its pretty easy. If you want an actual closed deal, not so easy. And of course check with your broker (as Super said) there is more liability.
Nothing like a pissed off client whom you promised I could sell the property, they loose the property, and blame you as the agent for it.