I have an idea that might be good that would be less likely to be misunderstood.
When you upload a video have a toggle bar to give it a rating like in the movies G, PG, PG-13, R
admin could also change and fix the rating for the video in siteadmin
with a statement that porn is not allowed.
Then on member preferences have a selection for safe viewing asking:
Block all videos with a rating higher than ( select rating.)
That way the member could self filter out media they find objectionable.
Just thinking out loud may be a dumb idea but just throwing it out there