I say yes,
Let's say someone is lying on the side of the road bleeding, people standing around not knowing what to do, the patient lying on the ground wondering if they will be ok.
The arrival of a professional in uniform, someone to control the situation will help put most people at ease, even if only a little.
It doesn't matter what qualification, as aussiephil said, anyone can do your basic ABC, apply pressure (in the above example) until a crew arrives.