When does ExecuteCodeWithGuaranteedCleanup actually guarantee cleanup?

Question

I have been reading about Reliability Features in .NET and have written the following class to explore ExecuteCodeWithGuaranteedCleanup

class Failing
{
    public void Fail()
    {
        RuntimeHelpers.PrepareConstrainedRegions();
        try
        {
        }
        finally
        {
            RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(Code, Cleanup, "fail");
        }
    }

    private void Code(object message)
    {
        // Some code in here that will cause an exception...
    }

    private void Cleanup(object message, bool something)
    {
        Console.WriteLine(message);
        Console.ReadLine();
    }
}

I have experimented with a variety of code bodies for the Code method. These, and their runtime results are listed below

Causing an OutOfMemoryException - Cleanup does not get called

List<string> ss = new List<string>();

while (true)
{
    string s = new string('x', 1000000);

    ss.Add(s);
}

Causing a StackOverflowException - Cleanup does not get called

Code(message); // recursive call

Causing a ExecutionEngineException - Cleanup does not get called

Environment.FailFast(message.ToString());

Causing a ThreadAbortException - Cleanup does get called (however a regular try...finally can also catch this exception)

Thread.CurrentThread.Abort();

So the questions are

• Am I using ExecuteCodeWithGuaranteedCleanup correctly?
• When is ExecuteCodeWithGuaranteedCleanup actually useful?