You can change user permissions on Web to control the access in which they have within Spotlight.
All users will have full access as a default and by restricting access they will no longer be able to remove/add users or edit Incident settings.
To do this first click on the "teams" icon in the left navigation bar.
Then select the relevant team.
After you have selected the relevant team, identify the user in which you would like to restrict access for and click on the "Access" drop down menu.
From here simply select "restricted" in the dropdown menu and click "ok" to confirm.
If there is any trouble in completing this action, please get in contact with Spotlight support we are move than happy to help.