Is it possible for VTScada to automatically display a page from the value of a tag?

Yes, but it will require some custom coding. You can create a simple module that does this and use a script tag or use page script to run the module only on specific pages.

Unless someone beats me to it; I'll run through some of my apps to look for some code examples I can share with you.

To clarify your request, are you ultimately looking to show a page or an alarm or something similar?

Ok, here are some links which might help here:

This page has some details on how to create a Go To Page Hook: https://www.vtscada.com/help/Content/p_Managers/p_PageHook.htm

This page is an intro into scripting and creating modules: https://www.vtscada.com/help/Content/Scripting/Tasks/pro_AddAModule.htm

What I would like to do is create a tag that is so to speak a takeover button, which if pressed would display a page that says this client or computer or something has been taken over by...so then any client with the tag would have this page without any controls on it, displayed so only the computer that took over the system would have access to the controls. And then I would create a tag that would in turn release the system back and the takeover page would no longer display to the other client computers and all controls would be restored to them.