They may 'accept the tip' and then try to verify/track it down with other sources (and say "I've heard X, can you confirm that for me?"), but no, a reputable journalist will never publish a quote from an anonymous source with no verification.

Unless they can verify it some other way, I highly doubt any reputable journalist would publish something like that. When a journalists publishes something based on a source that wishes to stay anonymous they are putting their career and reputation on the line.

A tip is just an investigative lead. "Hooker Chemical is dumping massive amounts of toxic waste at Love Canal" would be a tip. It would then be up to an investigative reporter to investigate, and report what the investigation uncovers.

You may be thinking of "unnamed sources" or "anonymous sources". Those people may be quoted on a factual basis, but the reporter has an obligation to obtain the same kind of confirmation of their information as any other investigative lead.

As an ex journalist, you might accept it as a tip and use it as the basis for further investigation. You wouldn't publish it.