Retrieving text value from ENUM by using int number that doesn't exist in said ENUM returns that int number in C#?

Question

I was reading official Microsoft C# documentation and examples on ENUM and there is a code in example that I don't understand.

public enum Season
{
    Spring,
    Summer,
    Autumn,
    Winter
}

public class EnumConversionExample
{
    public static void Main()
    {
        Season a = Season.Autumn;
        Console.WriteLine($"Integral value of {a} is {(int)a}");  // output: Integral value of Autumn is 2

        var b = (Season)1;
        Console.WriteLine(b);  // output: Summer

        var c = (Season)4;
        Console.WriteLine(c);  // output: 4
    }
}

The code block in question is

var c = (Season)4;

Documentation says that values in ENUM are associated with INTs that start with 0 and increase by 1 for each next value. So by this logic, Spring is 0, Summer is 1, Autumn is 2 and Winter is 3. There is no ENUM value associated with 4, yet VS shows not error and prints 4 when I run it.

I don't understand this behavior and it looks strange that VS doesn't mark this code block as error or warning. Wouldn't it be better to let a program crash to prevent more bugs when you try to retrieve a value from ENUM that doesn't even exist?