Probably plays well to the crowd at home, but if I were in Chinese high command they guy that authorised this would get fired right away. It's the most boneheadedly stupid thing they could have done. For what - to get back at Trump for taking a call from Taiwan? To rile the US? To thumb their noses at Yankee aggression?
Two words to China from the rest of civilisation - grow up
If you think your little outburst here didn't go unnoticed by everyone you're wrong, and if you weigh up the potential upsides vs the potential downsides then here goes - on the upside - china gets a commercially available drone that tracks salinity, and gets to play Hector Comacho with the USA. downside - this just went around the world - and China is forever looking less trustworthy and more coercive in every dealing.
Well played douchebags.