Absolutely so I have a budget DateJust which I only ever wear on a leather strap, as it's as a replica of a costume piece from a show, but moving asside from that, when I first got the watch, if I recall, it fogged up during my flood test, despite having all appropriate gaskets Maybe just a tiny breach around the crystal, and not really an issue when the watch is only ever worn on leather and never intended to get wet, but as you say, it's the principle of it... The DJ would've cost the factory more to make than the £15 sub, which has not just one, but two gaskets on the stem of the crown to create the water resistance, so as you say, what's the factory's excuse...
[Edit to add] The £15 sub is plastic...