Gas can mount on top of spare tire on back wall of trailer

Well, upon looking at this mod--it does look to be a bit insecure. I can't help but think the sight of this set up would make the "tail gater" back off somewhat, actually making everyone's trip safer.
We've all seen many rigs with gas cans and generators on the back bumper or attached with brackets. There really is not a way to transport extra gas safely in most cases. Fortunately, there aren't many accidents where this seems to be a problem.
This mod seems to be pretty well constructed--good on you.