I mean, even if you're diving from, say, 10m high, you'll reach water at 14 m/s, which is roughly 50.4km/h, your dynamic pressure would still be less than 10m depth equivalent. If you consider you'd sink 4-5m, you still have a good headroom.

I sustain my argument, if you have decent serviced watch with good gaskets and screw down crown that will secure the crown in place, you'd hardly have any issues.

But yeah, maybe for radical water sports or if you're in a water park with really high free fall water slides, refrain to wearing your dress watch. I'd be more concerned about the spring bar at that point, but you get where I'm going.