How does one prevent or correct this?
I don't think there's too much you can to in prevention. Some people are putting in these "catch cans" which are little vapor mist separators to clean up the PCV line to prevent crankcase oil vapors from getting in the dry intake. The can is occasionally inspected and drained. Engines like some Hemis that are run hard fill up those cans. Keep in mind that the Hemi is not direct injected it's only an example of how some are keeping the intake dry.