When installing 9.3-RELEASE (also true for 9.2-RELEASE) the installer only allows 15 characters for naming mount points when creating filesystems. This is unnecessarily short. For example, something as simple as /usr/local/tinderbox does not fit into this limit.
15 characters seems arbitrarily short. I would suggest at least doubling that, if not extending it all the way to whatever the actual limit is on mount names in fstab.