Should Draft Be Used For New Roles?

To clarify, when someone who mains adc, for example, might want to try jg, is it acceptable for them to queue up in a [Normal, not Ranked] draft with jg as their primary? Or would that be considered taking the role away from someone who might be better at it, should they stick to blind and just hope they can call in time?

Personally, the problem I have is that my client lags even though my game doesn't. All of my loading times are quite long, so 95% of the time when I'm in a blind, every other role is already called. That other 5%, it's usually top or adc that hasn't been, never jg. So, if I ever want to practice a role, I have to draft for it. However, I've seen other people do the same thing and have everyone report them for it, and (as a mid-mage main) having queued and gotten jg (Yi, who I at least knew, even if I wasn't great/experienced), I went 0/10/3 before I got a kill (which became a triple), ending with 6/17/12. I was reported for Inting, even though in champ select I stated I was inexperienced at jg and not great at Yi. Nobody offered to swap roles, and it wasn't until the match started that I ended up getting flamed, with people from both sides saying that "I shouldn't queue in draft for a role I'm not good at."

We ended up winning the game anyways, and I'll be the first to admit I still suck at jg, but the practice was helpful.

So, from a community perspective, is there a different/better way to learn jg, or should you be able to draft for a role you don't know without having everyone report you?

[Disclaimer: The primary instigator of the flaming/insults was also reported by other people on our team and took a penalty for verbal harassment, and I didn't take penalties at all, but it's about the principle of the thing.]