一直以爲是個規定而已，默認，也許有會計上的考慮，或者人們忘記，給一點充裕時間，3.1日照樣可以忘記呀。更多的個人認爲，弄巧成拙，誤解出現很多。稍許Google了一下，只找到下面的解釋，即認同又不認同 -------總而言之，沒能回答你的問題，只是一些我的comments

How RRSP tax deadlines work. The Canada Revenue Agency (CRA) lets you make RRSP contributions for the previous tax year in the first 60 days of the following year. They do this to give you time to find out how much employment income you earned in the last tax year and contribute accordingly