There was no rhyme or reason to

Air Milesという会社のポイント交換の製品に会員のランクによって違いがあったため，利用者から批判を受けたようです。

Air Miles backs down, alters rewards program under pressure from collectors

After hearing complaints from customers this summer, Air Miles tells CBC News it has changed the rules of its loyalty program.
The company explains that it previously gave members access to different rewards based on their individual personal preferences.

The loyalty program tells CBC News that "from time to time," up until the new change, it based what rewards people could access according to their personal preferences and shopping habits "to give collectors a tailored experience."
That explanation doesn't make sense to Wells. "There was no rhyme or reason to what I was seeing in my husband's account and my father's account. They were just random things. Like, neither of them have babies, but there was baby stuff."

http://www.cbc.ca/news/business/air-miles-rewards-program-1.3791477

今回取り上げる表現は，“there is no rhyme or reason to”です。“rhyme”には，「韻」や「押韻」などの意味がありますが，上記の表現になると，どのような意味になるのでしょうか。

『ジーニアス英和辞典』（大修館書店）を確認してみると，“there’s no rhyme or reason to[for]”で「に対してまったく意味を成さない」，「筋道が立っていない」と定義されていました。さらにCollins Dictionaryを調べてみたところ，“rhyme or reason”で“sense, logic, or meaning”とあります。ここでは，過去を表しており，「口座を確認した意味がなかった」などとなるのではないでしょうか。

またこれに関連して，“without rhyme or reason”という表現もあり，意味は，「わけもなく」，「なんの道理も説明なく」です。(Nao)