mouse_event vs real mouse event

Question

1. Is there a difference between a real mouse click (by hand) and execution of the click from code (by mouse_event in c#)?
2. Similarly, is there a difference between the real moving the mouse cursor and setting Cursor.Position?

If there is a difference:

1. How to recognize source of that event?
2. There is a way to simulate a mouse click / cursor move as if it came from a mouse or keyboard driver?

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Edit1: Code sample added for @Marco Forberg.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    [System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, CallingConvention = System.Runtime.InteropServices.CallingConvention.StdCall)]
    public static extern void mouse_event(uint dwFlags, uint dx, uint dy, uint cButtons, uint dwExtraInfo);

    Button button;

    private void Form1_Load(object sender, EventArgs e)
    {

        button = new Button();
        button.Text = "Click";
        button.Location = new Point(50, 50);
        button.Size = new System.Drawing.Size(100, 20);
        button.Click += button_Click;
        Controls.Add(button);

        Button simulate = new Button();
        simulate.Text = "Simulate";
        simulate.Location = new Point(50, 100);
        simulate.Size = new System.Drawing.Size(100, 20);
        simulate.Click += simulate_Click;
        Controls.Add(simulate);

    }

    void button_Click(object sender, EventArgs e)
    {
        Console.WriteLine(sender);
    }

    void simulate_Click(object sender, EventArgs e)
    {
        Point location = button.PointToScreen(Point.Empty);
        Cursor.Position = new Point(location.X + (button.Width / 2), location.Y + (button.Height / 2));

        mouse_event(0x02 | 0x04, 0, 0, 0, 0);
    }
}

Answer 1

There is no difference if you create proper Event arguments. The only way to find out that event is from "machine" is to analyze moments.