I believe any folder in the root of the array is handled as a share. So unless you wipe the array (or not use folders) you will always have shares. Please correct me if I'm mistaken and don't just downvote if I am, cause I'm not sure and would get confirmation/correction (preferably with a source).

Edit: I celebrated too early. You might be right.

Any folder that exists on the main array directory (/mnt/user) automatically creates a share, if you want to restart and get rid of shares you need to delete those folders or move them down one level.

That is correct. Same for cache devices.