Free BT Wi-fi for a Plusnet Customer ?

[#1]

I have my landline with BT, but for a number of years my broadband has been with Plusnet.
I am registered with MyBT for billing purposes and have just received a strange email from them.
In it it invites me to "Login With BT Wi-fi"
There's a link which I have followed so far which asks which operating system I am using and so on.
It states "Connecting to free BT Wi-fi couldn't be easier".
Does anyone know what's going on ?
Are Plusnet customers to be given free external Wi-Fi ?
Or is something more sinister going on ?
My surname does come at the beginning of the alphabet 'so perhaps other people haven't heard yet.
Any  thoughts, I certainly don't want to be bumped.
Oldgeezer

[#2]

What is the link?

[#3]

@oldgeezer  Could be a "phishing email". Don't put any username or password or other personal info in any links from this type of email.

[#4]

I also still have a "live" bt login, even though I haven't been a customer for several years.
Just checked and I was offered the same
BUT it asks for
BTinternet email address/password
to log in.
So it is a generic email and doesn't apply to us. (PN Users that is)

[#5]

So it seems that someone at BT  assumed that everyone with a MyBT account was also a BT broadband customer.
Not like someone connected to BT to make a mistake !  
Oldgeezer