Don't know about etiquette but on Sunday afternoon I'd have offered cold, hard cash for a tow back up the V1.
Made the mistake of thinking the NEish crosswind wouldn't make much difference on the way back. As soon as I turned at Coomera it felt like I'd entered a wind tunnel. On the positive side - the hills provided a bit of a wind shadow so getting over them seemed relatively easy in comparison. The other positive was spying a black cockatoo for the second time down that way. Not a single other cyclist. Seems I was the only one stupid enough to head out that late. Did I mention the computer was showing 34º as I set off?
And, as is often the way with the wind around here, nearing home and heading SWish along Clarks Rd I was still getting the occasional strong gust directly in the face!

I was trying to decide if I was stuck in a cyclone or just cursed, then I felt something between my shoulder blade and spine pop as I got out of the saddle to negotiate the intersection with Drews Rd, felt the twinges getting worse as I continued, and knew it weren't no cyclone.
Still, had a great trip down, saw a bird I've only ever seen once before when not in the mountains, and went for a very pleasant hour's spin this afternoon without too much complaining from the back.
But enough about me. Back to you...
Asking politely seems to work well in many situations.