In a recent case before the National Labor Relations Board where a union organizing drive was agreed to via a formal Election Agreement, the employer lost the organizing election by a vote of 17 to 14.
The date the ballots were due at the National Labor Relations Board via mail was the date that the total received were counted. However within the next 48 hours an extra 7 more ballots were received that would have clearly made the employer win the election. The employer cried foul because the ballots via postmark were clearly mailed well in advance of the normal time for the National Labor Relations Board to have received the ballots via U.S. mail. However, given how wonderful the U.S. mail system is, even though these ballots were mailed many days in advance of the due date, they were not received on the date the ballots were to be counted. The NLRB ruled that an agreement is an agreement is an agreement and therefore the employer was stuck with the date for counting ballots as indicated in the election agreement and there was no turning back the clock.
Lesson to be learned - never agree to a union election via U.S. mail ballot as opposed to in person balloting. No one can rely on the post office no matter how soon you mail your ballots. At our own law firm, sometimes we receive letters from the NLRB, just 15 miles away from our office, a week to 10 days after they were postmarked.