Recently, I went to close my fiscal year, and noticed that the net surplus did not equal my trial balance. After much testing, I found that two invoices had been entered in the AP module with the class field (usually UR, TR or PR) blank. I was able to adjust but I'd really like to make that field required so this doesn't happen again.
This requirement would be set at the GL Fund level. In General Ledger > Configuration > Funds, open the appropriate fund and ensure that Required on Accounts specified is set to All Accounts - this will make it so that entries to either Balance Sheet or Income Statement accounts requires class in all areas of The Financial Edge. I would suggest ensuring you have a backup done before performing this action in case you changed your mind after changing this setting. Some changes to a fund record can only be undone by going through Update fund transaction requirements (found in GL > Administration) which will overwrite historical data.
I will need to go into database view, but my understanding is that there are configuration settings that will prevent this.