Oh right. I've just never encountered such issues in the years I've been using FreeBSD, with /usr/local being one big partition.
I'm aware of that if no partitions are filled it causes an domino effect if not on its own partition. I have ZFS quotas configured so surely that mitigates the issue?
OpenBSD prohibits this except when code is run from a partition that permits it by means of a mount flag. Otherwise you get a core dump.
And all the partitions are largely an availability feature: if errant code fills up /var/log then /home is still usable.