@trusted and return ref

[Kagamin via Digitalmars-d-learn]

If one wants to prevent a leak, then counter can be wrapped
---
struct Unsafe(T)
{
    private T _payload;
    T payload() @system { return _payload; }
    alias payload this;
}
---
And somehow disallow Unsafe template in safe function signatures, 
then having
Unsafe!(int*) _counter;
would be ok?