비영리기관의 세금보고의 경우 우편이 가지는 약점을 대비하기 위하여 아예 certified mail을 사용합니다. 물론 일반 메일로 보내는 것도 개인의 자유입니다. 다만 결과에 대한 책임은 자신에게 있는 것입니다.
(IRS Publication 17)
Your paper return is filed on time if it is mailed in an envelope that
- is properly addressed,
******************* has enough postage,********
- and is postmarked by the due date.
If you send your return by registered mail, the date of the registration is the postmark date. The registration is evidence that the return was delivered. If you send a return by certified mail and have your receipt postmarked by a postal employee, the date on the receipt is the postmark date. The postmarked certified mail receipt is evidence that the return was delivered.