Leap, MeshColliders, and Collisions OnCollisionEnter not being called?

I have an asset from the asset store called Piano which as the following settings and the script ‘KeyToucher’ attached.

Keytoucher.cs contains very simple script:

using UnityEngine;
using System.Collections;
public class KeyToucher : MonoBehaviour {
	void Start() {
		Debug.Log("Pianologger engaged!");
	}
	void OnCollisionEnter(Collision other) {
		Debug.Log("Collision!");
	}
}

However, when I use the leap hand to touch the piano anywhere… the OnCollisionEnter function is not called? This has been driving me nuts and while I can get the debug statement in Start() to fire off, the OnCollisionEnter statement does not! Any ideas?

Self-answer five!

My issue was I was using the TrinusVR - LeapMotion example from GitHub - haelmy/TrinusLeapMotionExample
Where the demo was only set up with the capsulehands elements in the Hand Pool Script Array.
Adding the RigidRoundHand L and R elements after changing the array size to 4 resolved the issue.

Gratuitous links and explanations added to hopefully save someone many hours I had spent experimenting. Keep going noobs!