Yes, I got "duped" into this the other week when I booked a flight to Frankfurt. Surprised to find the policy documents appear in the post.

I called BA and they agreed to cancel the policy, but I had to send the documents back to them. I inserted a letter telling how underhanded I thought this was and firmly believed they should not have the box "ticked" by default. I told the guy in BAEC the same, only to receive no comment back...

I then marked the envelope "return to sender" and popped it in the post. buggered if I was paying for their cheeky attempts at increasing revenue