I've never seen that, but it's interesting.
How much head can it take in reverse flow before it opens admitting to flow out the drain? I know that's not the primary purpose.
Any chance of it getting gunked up and sticking shut? I could see a case where maybe liquid laundry detergent or some other gunk flowed into the drain and it caked/dried up sealing it shut.
Would it seal around grit, sand, pennes, screws, anything else that falls onto the floor and ends up in the drain causing it to fail open?