Service tag is created for both JDK and JRE on Solaris and Linux but it's only created for JDK on Windows but not JRE. Service tag is created if the Service Tags software is installed on the system.
There is no impact to the Windows JRE installation. The JRE installer should be modified in the postinstall step to call java com.sun.servicetag.Installer to create a service tag. No registration will be done.