A simple script written in C# that can lock a game objects position, rotation or scale independently or set a global lock to prevent those values from changing.

using System;
using UnityEngine;
using System.Collections;

public class GameObjectLock : MonoBehaviour
{
    // holds state weather or not there is a total lock in place
    public bool IsLocked;
    private bool prevIsLocked;

    // holds state weather or not there is a specific lock in place
    public bool IsPositionLocked;
    private bool prevIsPositionLocked;
    public bool IsRotationLocked;
    private bool prevIsRotationLocked;
    public bool IsScaleLocked;
    private bool prevIsScaleLocked;

    // used to store the state of the position/rotation/scale at the time of the lock
    private Vector3 position;
    private Quaternion rotation;
    private Vector3 scale;


    // Checks to see if a lock state has changed and if so performs a callback
    private void CheckLock(bool locked, ref bool prevlocked, Action callback)
    {
        // if locked but was not previously locked then perform callback
        if (locked != prevlocked)
        {
            if (locked)
            {
                // changed to a locked state so do callback
                callback();
            }
            else
            {
                // restore values
                this.SetLockedValues();
            }

            // set previous locked state
            prevlocked = locked;
        }
    }

    // Update is called once per frame
    void Update()
    {
        // if totally locked but was not previously locked then capture state of position/rotation/scale
        this.CheckLock(this.IsLocked, ref this.prevIsLocked, () =>
            {
                this.position = this.transform.position;
                this.rotation = this.transform.rotation;
                this.scale = this.transform.localScale;
            });

        // if position locked but was not previously locked then capture state of position
        this.CheckLock(this.IsPositionLocked, ref this.prevIsPositionLocked, () => this.position = this.transform.position);

        // if rotation locked but was not previously locked then capture state of rotation
        this.CheckLock(this.IsRotationLocked, ref this.prevIsRotationLocked, () => this.rotation = this.transform.rotation);

        // if scale locked but was not previously locked then capture state of scale
        this.CheckLock(this.IsScaleLocked, ref this.prevIsScaleLocked, () => this.scale = this.transform.localScale);

        // if is locked then ensure position/rotation/scale are set to the same values they were at the time it was locked
        this.SetLockedValues();
    }

    // used to set the position/rotation/scale is they are in a locked state
    private void SetLockedValues()
    {
        if (this.IsLocked | this.IsPositionLocked) this.transform.position = this.position;
        if (this.IsLocked | this.IsRotationLocked) this.transform.rotation = this.rotation;
        if (this.IsLocked | this.IsScaleLocked) this.transform.localScale = this.scale;
    }
}