$sessionConfigurationDll = [IO.Path]::Combine([IO.Path]::GetTempPath(), "ImplicitRemotingRestrictedConfiguration$(Get-Random).dll")
Add-Type -OutputAssembly $sessionConfigurationDll -TypeDefinition @"

using System;
using System.Collections.Generic;
using System.Management.Automation;
using System.Management.Automation.Runspaces;
using System.Management.Automation.Remoting;

namespace MySessionConfiguration
{
    public class MySessionConfiguration : PSSessionConfiguration
    {
        public override InitialSessionState GetInitialSessionState(PSSenderInfo senderInfo)
        {
            //System.Diagnostics.Debugger.Launch();
            //System.Diagnostics.Debugger.Break();

            InitialSessionState iss = InitialSessionState.CreateRestricted(System.Management.Automation.SessionCapabilities.RemoteServer);

            // add Out-String for testing stuff
            iss.Commands["Out-String"][0].Visibility = SessionStateEntryVisibility.Public;

            // remove all commands that are not public
            List<string> commandsToRemove = new List<string>();
            foreach (SessionStateCommandEntry entry in iss.Commands)
            {
                List<SessionStateCommandEntry> sameNameEntries = new List<SessionStateCommandEntry>(iss.Commands[entry.Name]);
                if (!sameNameEntries.Exists(delegate(SessionStateCommandEntry e) { return e.Visibility == SessionStateEntryVisibility.Public; }))
                {
                    commandsToRemove.Add(entry.Name);
                }
            }

            foreach (string commandToRemove in commandsToRemove)
            {
                iss.Commands.Remove(commandToRemove, null /* all types */);
            }

            return iss;
        }
    }
}
"@

Get-PSSessionConfiguration ImplicitRemotingRestrictedConfiguration* | Unregister-PSSessionConfiguration -Force

$myConfiguration = Register-PSSessionConfiguration `
    -Name ImplicitRemotingRestrictedConfiguration `
    -ApplicationBase (Split-Path $sessionConfigurationDll) `
    -AssemblyName (Split-Path $sessionConfigurationDll -Leaf) `
    -ConfigurationTypeName "MySessionConfiguration.MySessionConfiguration" `
    -Force

> $PSVersionTable
PS C:\> $PSVersionTable

Name                           Value
----                           -----
GitCommitId                    v6.0.0-alpha.11-51-ga0dbd11bc2fdd5f4b090b534043f582325535b2a-dirty
PSVersion                      6.0.0-alpha
CLRVersion
PSEdition                      Core
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
SerializationVersion           1.1.0.1
PSRemotingProtocolVersion      2.3
BuildVersion                   3.0.0.0
WSManStackVersion              3.0