[TYPO3-dev] Why are timestamp fields NOT NULL?

[Sebastian Michaelsen]

 From now and then I stumble upon something like this in TYPO3:

01-01-70 (-41 years)

In most of the cases that's of course not correct because there's simply no date given, but TYPO3 
can't distinguish between no date given and date = 0, because all the timestamp fields are NOT NULL 
(example: pages.starttime and pages.endtime).

Is there a certain reason or should we change it to allow NULL in the database?

Kind regards,

Sebastian