I also assumed the number field was all that was needed.

I had fraudulent checks used under my name. And it was only caught because the thief signed my name “perfectly”. Where I purposely sign with extra scribbles.

After that experience, every check I wrote, I added something extra in the memo section only I would know. I could see someone being extra paranoid and using the “written” section as another test - like purposely misspelling words.