When I worked for a company that made label printers we had a potential customer who wanted us to print labels with human readable and barcode fields with 4 ran

When I worked for a company that made label printers we had a potential customer who wanted us to print labels with human readable and barcode fields with 4 random letters and 4 random digits but did not want the letters to spell any obscene words. We asked for a list of words to ban but they declined to provide such a list. We did not get the contract.