This is a tricky one. At some point in the future we may be able to introduce a sub-category of sentences that are user submitted, and are either viewable/hidden based on a voting system by other users. However, I am not certain that this is something that we would get native speakers to check as part of the process.
The main reason for this is that checking sentences, thinking about a situation they could sound natural in, and also what context the writer wrote them in would actually be more time consuming than it would take a native speaker to write a natural sentence themselves.
This is based mainly on my experience checking English sentences written by Japanese students. Sometimes they ask me if it was right, I need to say āWellā¦ I mean I guess grammaticallyā¦, But what did you actually āwantā to sayā. Then when they tell me what they wanted to say in Japanese, I would either say āOh yeah, in that case itās great!ā, Or āOhhhh, I see, actually that word has a different nuance in Englishā. Due to this requirement to check āwhat did the writer actually meanā, it would greatly greatly slow down the rate at which sentences were added.