I think the growing assumption that policing is a job only for professionals is wrongheaded and reinforces the divide between police and the rest of the citizenry. As Robert Peel stated, "the police are the public and the public are the police; the police being only members of the public who are paid to give full-time attention to
duties which are incumbent upon every citizen in the interests of community welfare and existence" (my emphasis). When the police think they are separate from the rest of us it leads to authoritarian, entitled, and out-of-control police. When ordinary citizens think they are separate from the police it leads to a freer hand for criminals.
Your point about "non-professional" persons is well taken, though. There certainly is a limit to what a citizen should be expected to do. I think keeping tabs on a criminal or suspicious from a safe distance is not asking too much.
“If you SEE something - SAY something!”
If we don’t show up in time to CHANGE something, uh.... just ferget it.