CUPS BSD and system V print compatibility system is installed.

This port installs binaries (lpr, lpc, etc) which have the same names as
binaries in /usr/bin and /usr/sbin. Assuming you installed this port to use
cups fully, the minimum you need to do is make sure all users PATH variable
has %%PREFIX%%/bin before /usr/bin. As this is not always easy to do,
a you may consider removing the FreeBSD printing system completely. To do this,
remove the binaries and man pages listed below, and set NO_LPR=true in your
/etc/make.conf. This will prevent future buildworlds from re-installing the
binaries, but will not prevent them from getting re-installed during a binary
upgrade.

The relevant files for the FreeBSD printing system are:
(with wildcards to make it easier)
/usr/bin/lp* /usr/sbin/lpc /usr/sbin/lpd /usr/share/man/cat*/lp*
/usr/share/man/man1/lp.* /usr/share/man/man1/lp[a-s,u-z]*