What provisions exist to handle scooping when there are multiple reviews of research papers? Point 1: At my university, it's a practice (not compulsory) to submit our conference/journal paper first to a department where it is checked for plagiarism and quality. Then it's sent to professors in the university to confirm that they don't have any authorship problems with it (ie: that the student didn't copy one of their ideas, unacknowledged). It's only then that the student gets approval to send the paper to a conference (specifically this one) or journal.  

Point 2: A journal or conference has it's long procedure of reviews and only some papers get accepted. If rejected or un-published, the author can send it to another conference or journal and there's a similar lapse of time.  

During both above situations, isn't it possible for someone else to scoop the idea? Does the academic community have any provisions to prevent a planned scooping? ie: Someone reviewing the paper purposely rejects it and during the time that elapses, publishes the same idea or allows one of his/her other students to publish the idea.  

A teacher of mine says that it's because of these fears that she directly submits papers to conferences without going through the university's process. Also, the same reason she submits to conferences instead of journals, because the journal review process is much longer, increasing the scope of the idea being scooped.  

So are there any safeguards? If I see my idea scooped somewhere, would it help if I can show proof that I had already submitted the idea at a conference and the paper was rejected? Will the person who supposedly scooped it, get blacklisted?
After writing to a number of journal and conference organizers, KDD and IEEE responded by saying that putting up a document on arXiv and then submitting the same document to one of their conferences or journals is ok. IEEE officially mentions it here. There's also a nice answer here.  

UPDATE:
As of 2019, KDD no longer allows pre-prints on ArXiv due to their double-blind policy.
As of 2020, IEEE started their own archive named TechRxiv, and they still allow pre-prints on ArXiv and TechRxiv.