Consider using /etc/defaults/vendor.conf

[probonopd]

Consider using a /etc/defaults/vendor.conf file as documented in https://www.freebsd.org/cgi/man.cgi?rc.conf rather than fiddling around with rc.conf like we do now.

That would probably be cleaner?

[crees]

This is exactly what the file is for- there are no downsides at all as far as I can see. It also means that the user's changes in rc.conf can be undone by removing it, the upgrade path is clear and conflict free.... all in all, yes, a perfect idea.

Should be as simple as installing helloSystem's rc.conf there instead.