Carbon arrows for non all-carbon arrow competitions

I've been to a few comps, well more than a few, that state 'please no all carbon arrows unless they have been made detectable with a metal detector'. Now leaving aside the obvious points, it is not clear whether they mean the whole arrow or a significant part of the arrow. Assuming the answer is a 'significant part' I have just tried the following that works really well and easily detectable.

The above arrow is...

Carbon arrows for non all-carbon arrow competitions