We have removed access to Ideas for the moment. However, if a user goes the "+" icon they can still add an idea. They add an idea and then they cannot actually access it. If a navigation item is removed, it should be removed from the "+" icon as well.
Whilst I am expressing this for "Ideas", this should be relayed fr every entity where you can remove the display of it, show remove the display of creating a new item of that type in the "+" drop down as well.
Thank you for the idea. Given the low volume of support for this idea, we do not have plans to make updates in this area at this time. We hope you can understand.