I know, especially in my early teaching years, that I've used little (sometimes meaningless) math tricks to get kids to "remember" a procedure or computation rather than a concept. Did it make me a bad teacher? No, I don't think so. I really believed that it was my job to make the material as easy as possible for my students. Now, not so much. It's not my job to make the work any easier, it's my job to know how to get my students to where I want them to be. It's my job to constantly ask them questions what what they are thinking and to challenge their thinking to push them forward so that they can make sense of math on their own.
What I found most interesting (and not that surprising when I think about it) about this article was how many of the "rules" "expire" in 7th grade. As a 7th grade teacher, I have seen the faces of students so many times, when I am teaching them something and all of a sudden something they thought was "true" turns out to not be as true as they thought. For example, leaving improper fractions as improper, or using the number line to show how you can subtract a bigger number from a smaller number. The article also made me aware of some of the things that I have presented to my scholars as "true" and how I can catch myself in the upcoming school year. I am so grateful for having taught 8th grade and Integrated Algebra in the past because it gives me a frame of mind when I am teaching my 7th graders for where they will need to eventually be.
In addition, someone shared this free resource, Nix the Trix, which also does a good job of describing tricks, rhymes, etc, that are commonly used by teachers that "rob students of conceptual understanding." Had to share!