man 5 exports describes different defaults as implemented - subtree_check

ubuntu 9.04 x64;
create a new nfs export with line in /etc/exports like:
/home/hamster/Public 192.168.75.0/255.255.255.0(sync)

the man 5 exports page says:
The default of having subtree checks enabled, can be explicitly requested with subtree_check.

However running nfsexportfs -a reports:
Assuming default behaviour ('no_subtree_check').

The default behaviour should be changed to match the man pages, or (worse) the man pages made to match the default ubuntu action of no_subtree_check. Note that man 5 exports clearly states that 'no_subtree_check' is less secure:
no_subtree_check
              This option disables subtree checking, which has mild security implications, but can improve reliability in some circumstances.