Why can't rule types support locking?

I created a custom rule type and needed to enable locking for it (-ie- checked locking on class form).  Now I can't perform a rule checkout of instances of this rule type because the rule checkout code does not lock the instance and so upon saving of the checkout the lock is not held and and error occurs.  I tried overriding PreCheckOut and performing an Obj-Refresh-And-Lock but that does not help.

Can rule types just not support locking?