I would not call being pushed 2v1 with almost no cooldown abilties an enjoyable experience.
Jungling presents no risk to the jg if the enemy set up is 2-1-2, but it is hell for the 1v2 lane.
With the nature of random champ select, not all champ can 1v2 at all and even if they can, not every player wants to opt for 1v2.
Before deciding to jg, you will want to check to make sure your team is fine with it, most especially the 1v2 guy.
If your team is okay with having jg, then there would be no "report jungler" now would it.
The problem comes from you forcing your way into jungle and leave the odd man 1v2 to face the consequence of your action. If your team is not comfortable with having a jungle, then dont jungle. Just like the non-meta stuffs.
While i agree it is not punishable/reportable offense, forcing your way to play onto 4 people who do not want to deal with 2-1-2 in urf will cause some hard feelings and flames that will eventually becomes punishable/reportable.
TL:DR - make sure your team is fine with having a jungle in urf. Just like non meta strategies in normal, if you force it on the team that do not want to play with it, prepare to face the consequences.