“Russia is already in Syria. Wouldn’t take much for their planes to accidentally stray off course and bomb the wrong strategic oil field.”
That would be a suicide mission against the Saudi air defense system.
It's not as if Arabs don't have a preponderance to over estimate their abilities. Give them a new toy and they have more swagger than John Wayne.
I doubt the Ruskies would be any more deterred by it than we would (If we had a rational leader)