an ambulance at the bottom of a cliff

an ambulance at the bottom of a cliff

Something that is helpful only after one is already injured or in trouble. The idea is that, while an ambulance at the bottom of a cliff can help people who fall off the cliff, a fence at the top would be more beneficial. Services like this, which only help kids once they've gotten into significant trouble, are like an ambulance at the bottom of a cliff.See also: ambulance, bottom, cliff, of