This question was recently asked “She ran… , her nose pressed against the glass” Are the actions simultaneous or consecutive?. Edwin Ashworth (correctly in my opinion) asked the OP for surrounding sentences. I also asked for the source.
I have noticed many people post sentences asking if they are "correct." Sometimes they cite a source, but most of the time, the OP does not cite a source and people don't generally ask for one. Then the guessing and hypothesizing start. I've noticed in many of these questions the OP doesn't respond to requests for further information, or doesn't mark an answer as "best answer."
I feel that answering whether or not a sentence is correct or not is largely dependent on seeing where it came from. It is more likely that if the sentence came from The New York Times or The Economist or even Harry Potter it is more likely to be "correct." If not, we can see that there is a typo that clarifies things or the surrounding context helps see that the sentence is "correct" but could have / should have been written in another way, or perhaps the sentence is an example of BrE / AmE / IE, etc. Sentences that are made up or invented (in my opinion) stand a greater chance of being ungrammatical or illogical. In the example I cited above, if the OP answers, "I just made it up." then it is easy to answer by explaining "Sentences in English should have this construction..." If we don't know the source, then people need to make an assumption that it did come from a source and the answers will have a "justification" feel or will try to figure out what the original writer of the sentence meant.
I feel that we should ask for sources. If one can't be provided, I feel that is OK but it must be stated in the question that "This sentence is invented." The sentence could have been invented because the person is reading a grammar book and wants to know if their invented sentence complies with what they were learning. Answers to these kind of posts are valuable because they provide help to others who may be thinking the same thing...usually questions about certain grammar points are common. For example present perfect, semicolons, or the recent question about past progressive and the use of "when." past progressive with dependent clause -- dependent clause types in the face of ambiguity
Should we be asking for sources? Should a question be closed if, after a reasonable amount of time, the OP can't provide a source or explanation?