Windows 7: How did it know?

I was trying to activate my new debit card using my cellphone with bluetooth earpiece. I dialed the number and got the welcome message but then it disconnected. I assumed that there was some problem and would try again later.

So, during a break at work, I tried again but without the bluetooth. I got the welcome message and the prompt to enter my account number, but since I didn't have the card on me at the time I terminated the call.

When I got home, tried again (with bluetooth). Welcome message and disconnect. Hmm...tried it without the bluetooth, success! Weird, so I activated the bluetooth and called again. Welcome message and disconnect.

I can see the security issues in using a bluetooth earpiece when dealing with sensitive information, but how did the system know that it was in use?

Is Big Brother watching?

Kent