For Umbraco, the ability to not render any user permissions tree nodes based on the current user

DisableUserPermissionsNodes.cs

using System.Threading;
using umbraco.cms.presentation.Trees;
using Umbraco.Core;
using Umbraco.Core.Security;

namespace Test
{
    public class MyStartup : ApplicationEventHandler
    {
        /// <summary>
        /// Bind to umbraco events when the application is ready
        /// </summary>
        /// <param name="umbracoApplication"></param>
        /// <param name="applicationContext"></param>
        protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            BaseTree.BeforeNodeRender += UserGroupPermissions_BeforeNodeRender;
        }

        private void UserGroupPermissions_BeforeNodeRender(ref XmlTree sender, ref XmlTreeNode node, System.EventArgs e)
        {
            if (node.TreeType != "userPermissions") return;

            //get the current user
            var backOfficeIdentity = Thread.CurrentPrincipal.Identity as UmbracoBackOfficeIdentity;
            if (backOfficeIdentity == null) return;

            //check if it's the 'special' user
            if (backOfficeIdentity.Username == "UserAdmin")
            {
                node = null;
            }
        }
    }
}