We had a client that entered a credit memo in the year 8021 in the document date field. The system did not complain because the posting date is by batch and so the posting date is set to year 2013 and the transaction posted fine.
Later the client created a check batch and chose to automatically apply credit memo because she wants to print a remittance for that vendor. She got a weird error message. The problem she is encountering is documented in this KB article: support.microsoft.com/.../855322
By the time I had a chance to help her out, restoring the backup was not an option and I had to spend over 2 hours trying to fix the data and make everything post correctly because there are other transactions in the batch that posted and others are still stuck in that batch.
Anyways, the client and I think that it would be great if the document date also validates against the fiscal periods table to make sure the year is setup in there. Can you please add that as a suggestion please? Thanks!