Sorry if I wasn’t clear: I’m aware of why the message is there and it’s relevant to know when sharing. And as a Discourse admin, I understand how the permissions work. My quibble is that it says
Only visible to members of group: trust_level_1
Assuming that a user knows what trust levels are, they are less likely to be aware that whatever permissions a TL1 has, higher trust levels will have it to. And note that the sentence doesn’t mention permissions but groups: only members of particular group can see it, which leads to thinking that members of different groups can’t. Would make more sense if we were talking of some custom named group, but when the group is one of the trust levels, it can be confusing due to the permission inheritance that not everyone knows/understands.
Perhaps for trust level groups, this notice could list only the lowest one of them and include a “and higher” suffix — this would work even when the category setting only has trust_level_1. For other (non-trust level based) groups, they could be listed by their name as it is now. But, I reckon this is likely more complicated to implement, although less confusing for users.
I can think of a case where the behaviour as it is now is better.
You want to share a post with a user. So you want to first check if they are able to read the post. The popup tells you that you need to check if the user is in the trust level 1 group. So you check one group and konw wheater they can read the post.
If you also show all higher trust level groups it creates the impression, that you would have to check all of them. But everyone in the trust level 2 group is a member of the trust level 1 group, so there is no need to check that.
The message does not say “visible to users with trust level 1”. It says “visible to all memers of the group trust level 1”.