To my knowledge, Tygon is a brand name, and not a specification.
I expect you are referring to the F 4040A formulation of Tygon.
There are more than 2 dozen formulations of Tygon tubing, as exemplified by the link I posted. Some are NOT gasoline compatible.
3/16 does stretch/stress the tubing more than desired when placed over nipples expecting 5.5mm.
I've not seen Tygon tubing last 40 years. I have seen it harden in other gasoline environments, needing replacement, possibly from the alcohol contamination in the gas. I have seen Honda spec tubing last that long and still function well.
I use Tygon tubing in my r/c models that use gas engines. It works fine there, imo, as well as in the yard equipment I have.
I don't understand what manners have to do with component/application specifications. Inanimate objects don't care if they work or not.
Cheers,