I think if you're genuinely trying to avoid awkwardness you'd just share ... I mean how much stuff are we talking? A book and some rubbish from the in-flight snack that's yet to be collected? 
I can see the upcoming threads next to the ones about Y pax using the J lav ... Aisle pax put his newspaper on my Neighbour Free seat
Also, who's to say Qantas won't sell the "Neighbour Free" seat to both pax either side...