You can't add release info without a year. Not really a problem for new releases, or MB/discography experts but for people working through their CD collections this can be a showstopper as there is no easy way to get this info without a fair degree of internet research skill.
On the other hand, barcodes, cat numbers, format are generally pretty easy to figure out from the packaging.
(It's just occurred to me that this requirement could in fact encourage people to add the copyright year which is often present but often not the same as the release year)
It seems to me that this requirement may just have been a leftover from when there were fewer fields.
Prompted by discussion here: http://lists.musicbrainz.org/pipermail/musicbrainz-users/2008-July/018230.html
