Replaced Sky Router - Received Email on Contract Breach

[TimLondon]

I just replaced my Sky router for FTTP with a Deco X75 router (part of a mesh network).  I use Sky Stream and everything is working perfectly.  However two things are confusing me:

1) How does my setup even work?  I was expecting to have to buy a third party router (Vigour/Asus) that supports DHCP option 61.  I plugged the X75 in as a test (in Router mode) and it just worked

2) Within an hour I received an email from Sky stating that "It looks like your Sky Glass TV or Sky Stream puck might be being used to watch TV at another address.", and basically that this is in breach of our contract.

What is happening and should I be concerned?  Everything is working perfectly from my perspective.

Tim

[Tomwig]

AFAIK Sky no longer require DHCP option 61, I don't have it set up on my Unifi Router.

My understanding is Sky broadband is not a requirement for Sky Stream or Sky Glass.