Brexit for cold calling?

You may know I’m a Brit. At the time of this post, the UK government is going through it’s 27th vote on Brexit. (Actually I don’t know how many votes there have been. It’s unlikely anyone could agree on the definition of “vote”.)
I’m involved in helping companies sell more effectively. There is an issue in sales that is a lot like Brexit. It’s super-contentious and you can find people to argue for and against it, and probably have 27 discussions. That issue is cold calling.
When it comes to cold calling I am a “leaver”.
My best rationale for why is based on data. Data on this subject is hard to come by so whenever I see some that seems credible I save it. Here’s what I’ve got so far.
1.  Baylor University
In 2011, Baylor University conducted a research study on cold calling with realtors from Keller Williams. They ended up having 50 agents