Updating from selinux-policy-targeted-3.14.2-49.fc29 to selinux-policy-targeted-3.14.2-51.fc29 - the scriptlet turned my CPU into a grill, my X session and Xfce desktop crashed and dnf failed mid transaction.
Let me just say that if other RPM packages actually depend on /usr/bin/python3, you'll get /usr/bin/python3. However if non RPM software you use depends on it, you are now in trouble. So what you expect is a reasonable thing to ask.
I consider raising a new warning as a change of API, but I realize that it is probably disputable. Anyway, the update is in stable, probably to late to change anything, let's not bike shed then. I was surprised by this, and others might be as well. I'd consider an e-mail to dependent package maintainers as a reasonable thing to do.