Just to clarify, in the next update before classic release the auto invite is gone and only available for custom groups, not dungeons groups anymore. I put it in with the intention for big groups of people to do pvp for example. It just doesn’t make sense to use it for dungeons as you might end up with a group of 5 dps or healers.
On the other note, having guidelines for addon development doesn’t make sense. You need hard rules which is implemented in the ingame API. The question you should answer is, should addons be allowed to invite people to the group, not in which scenario it is fine or not.