Hey that is cool.   It does look like a magnet (almost weak refrigerator magnets),  also looks like holes at the top (safety overflow, good stuff) however one thing that is a bit odd near the end of the video it looks like as if its in full bore overflow for a moment before it pops, maybe magnets are a bit too strong?    Eh.. either way definitely got a cool factor going on.   Looks completely doable too,  hell Taps even sells the all plastic piano hinges.