Web Applications are STATELESS.
The Web Server cannot distinguish between your web session and my web session unless we give it a unique web Session ID.
If you stick with a common web Session ID between all end-user, then my Items will show up in your basket.
This is because we are using the same web Session ID.
What you desire does not conform to reality.
Don't do that. (ie don't use Session ID = 0)
Thanks Mike. It makes sense.
However being a public application and Search engine friendly what else can I do instead of using 0 session ID?
Public Shopping Cart!! Who are buying what?!
To build a search-friendly Website you could think in customization of Universal Theme to reach the look-and-feel you wish. Some pages of your Application would be public and some would require authentication and authorization schemes depending on your business needs.
In addition, if you don’t like Universal Theme, you could use Material APEX. However, it is not working fine with 18.1 until now.
I hope that helps