Fair points 'comfy chairs'.
I have been known on occasion to preface my 'threat' brief with the words 'things that can bite us on the backside during this approach/departure'. That actually enables me to expand on things that I've seen or heard of others stuffing up. These may not be threats in the pure sense of the word- as no management process may be needed- but they could become one later if circumstances change. Crossing an active runway in 'normal' circumstances wouldn't normally be considered a threat but given the config of Cairns then you're right about it being a worthy thing to talk about if it's going to come into play. Why is it a 'threat' and others not? It's something external to the crew (poor airport design) that requires an additional management step to avoid an error. Discussing it when landing on 33 (in the 767) would NOT be relevant.