There is permission for a non-rabbi to answer in the style of "maareh makom ani lach (I am a source citation for you)." If someone calls me and asks, "I have porkchops in my freezer, can I eat them?" it is not psak halacha for me to say no. I am still within the boundaries of this general permission without citing my sources.
In most cases, there are both questions of law and questions of fact which enter into what the halakha will be. However, sometimes one or the other is already obvious and known to all involved. I once asked a rabbi what bracha to make on a certain kugel. He responded "if it is noodles, say mezonot. If it is potato, say adama." That answered the question of law and not the question of fact. It was unhelpful because I knew that and wanted an answer to the question of fact. Absolutely anyone who knew the facts could have answered with the facts and it wouldn't constitute psak. If you read when sunset is in your local newspaper and use that to calcuate the tme for mincha, the newspaper isn't paskening for you.