I've never carried a siphon hose nor the need for one. I think it's kind of silly- if you can't read a gas gauge, especially one that blinks at you, and run out then you deserve to be walking. I'd just shake my head and call you a *******. I'll fetch you gas but you'll be left on the side of the road and I'll be taking my sweet-*** time. Ain't no man ridin' ***** on my bike. I have never once in or on any vehicle ever run out of gas. I can see the noted exceptions of out west and the distances between and the extra planning needed but really, running out of gas?
It's pretty easy to find that the gas station that was open last time you rode through is now closed. Many years ago, I rode with a friend on a XS11 Special that had a range of 120 miles - I had to share a lot from my C10 Connie. We would have to gamble on range a lot or we'd never ride anywhere. He carried a 1l fuel bottle that I could refill in a few seconds from the petcock on my bike.
These days, I carry a quick disconnect and some hose on my GSA. The QD plugs into the FI return line and pumps fuel at about 3 psi - perfect for sharing fuel. Since the GSA holds 30l, I'm never the one running out of fuel but the rule is that the person topping up from the GSA-tanker is the one buying the beer that night!
Since the FJR doesn't have a return line, it's not an option but I will probably rig something similar up to my Joe2lmaker tank when I install it.