Hi all.
I've got an upcoming flight with VX - my first!

I've just checked the flight to see if it was full (it's nowhere near) and noticed that (presumably) single travellers - or maybe couples being 'sneaky' and angling for some extra room - book seats so that the middle is empty. The flight is SFO-LAX so I can certainly see why you'd try. I've done this myself flying domestically with much success but I am not familiar with this route and how busy it can be i.e. if the flight is likely to sell out.
ANyway, on checking my flight today I noted that almost every middle seat is vacant except, of course, the seat next to us (we selected aisle and middle and someone has gone in a selected window)! So I'm thinking about changing seats and am wondering whether it's worth the gamble to use the method that is apparently subscribed to by others i.e. select window/aisle and leave the middle empty hoping no one takes/wants it.
The flight is in 5 weeks so there's plenty of time for it to fill but worse case scenario I guess we'd just ask our fellow passenger to swap with us and concoct some tale about selecting the wrong seats "oh silly us" or whatever???
Thoughts on this practice?