You have to understand that a Captivate course published to HTML5 is like a website. And a website is also only fully functional when it is on a webserver.   Locally previewing (using localhost) will work in some circumstances,  but not for everyone at all. What is so difficult about setting up a webserver? It can have limited access, only those having the URL will be able to see it. Your IT people will know perfectly that this can be done securely.

It was much easier with SWF output, when you could have an interactive pdf or an exe file available but that time is over and out.