Tails of the forbidden zone

Or, 'I said there are rules, Damnit!' (mostly)

I have told you how Tommy will not cross the kitchen floor into the rest of the house unless there are specific circumstances(rules). Someone at the front door; are you awake yet(walk time); where’s WG.
The other morning, while I was sitting at the kitchen table, putting my socks on(pre-walk), he came across the forbidden zone for a chin scratch. Now, this is permissible since he comes just far enough for me to scratch him under his chin. We do it most mornings.
Well this morning WG stood two feet from me, just outside the kitchen. She called Tommy, but he would only come as far the chin scratch mark, but no further. After all, there are rules!

So, Christmas morning and we are about to open our stockings. Our son comes into the den, and of course his dog Enzo(who has no rules) follows him in. As we are sitting there, WG comes in, turns and calls to Tommy.
And without any hesitation, Tommy walks across the forbidden zone, into the den and sits down at WG’s feet!

I am not sure if it was that our son was there, Enzo was there, or that we were all there. But it is amusing how the rules seem set in stone, but there are exceptions that only he knows about.