Non inheritable check constraint

I have gone through the issue of making a parent table not writable. After
discussing it (1) I adopted the trigger solution. But I think that a
trigger is just an invisible layer over the database model and so I'm
naively proposing a new syntax to postgresql. It would inform that the
check constraint is not inheritable:

create table t (c integer check NOT INHERITABLE (false));

I found a model visible solution but it only prevents non null values from
being inserted. Or only prevents all inserts if that column is not null:

create table tfk (c integer unique check(false));
create table t (c integer, foreign key (c) references tfk(c));

Regards, Clodoaldo

(1)
http://stackoverflow.com/questions/9545783/how-to-prevent-inserts-in-a-table