Microsoft SQL Server CAL - What is it? I have trawled through masses of documentation both on Microsoft website and Stack Exchange, yet I have failed to find answers to some basic questions:


What is a CAL? A license code that I need to enter? Or a legal document allowing me to use the software in a certain way? 
Let's say someone simply installs SQLServer 2016, restores a DB and points 200 clients to it via TCP/IP protocol on port 1433. Will the clients be able to connect and use the DB server? If not, what software exactly and on what side (DB server/client) will stop it from working? 


If you feel that I haven't searched well enough, would you be so kind and provide a link per each point above, leading to an exact answer (as opposed to several paragraphs of vague text that is usually found on MS website)
CAL is a legal CONSTRUCT. I say construct because you may not even get a dedicated document, depending on what papers you sign and agree on with Microsoft.
CAL's are not technically enforced. That said, if you ever get audited you will realize that you are still - possibly criminally - liable. It is legal construct and legal protection to software use applies, whether technically enforced or not.