PHP 5.4: why can classes override trait methods with a different signature?

I'm wondering if there is any good reason why this behaviour is possible in the current PHP 5.4 implementation:

trait T {
    public function test(PDO $pdo) {}
}

class C {
    use T;
    public function test(DOMDocument $dom) {}
}

I thought that the fact that a class uses a trait, guaranteed that this class had a specific interface available. But here, if we inadvertently override the trait method for another purpose, we don't even receive a Strict Standards notice, as with classic inheritance.

Is this specifically allowed on purpose? What for?