Registration system for gaming club (Windows)

I need to set up a game club management system. There is a server and more than 60 client computers. Which approach is best for a temporary registration system (customers have a credit balance, if they run out of money it will be automatically logged off)?
Windows login system or custom full screen login box that blocks Windows functions (Alt + Ctrl + Delete, Windows + D, etc.). Thanks a lot

magento2.3 – Add notification to Magento 2.3 Customer registration about shipping restrictions to California

I want to add a notification to display on the registration page – only if California is selected as the state. Otherwise it will not be shown. I am not sure of the parameters. I use Magento 2.3

The current code in the register.phtml file is as follows:

and my php is what doesn't work:

Please note: We do not ship to California.
';} else { echo '';} ?>