I get the idea of letting the server centralize logic like this - but frankly if the application is choosing to send all that data across the wire just to have the server throw it away the application is wasting network I/O. If it does manage its resources carefully then the server will never even see an update and its behavior here becomes moot.
I understand your point, it´s responsability of application to do what it has to do. But lots of times (maybe 98% of them) is not same people doing server side and application side. So, Postgres guys will have to review all code being done on apps ?