Thank you so much Rohit. You helped me notice something that somehow I had missed. Towards the end of the example in the documentation they use the Part approach and I guess my mind got stuck on it, I was simply surprised when I noticed that the [ ] worked, and frankly, I prefer it.
Again, thank you for clarifying this for me.
Now off to my code to replace all those uses of [[ ]] with [ ] when used with associations!