I think the title is misleading and a little unfair to the wonderful work Microsoft did with Merge (Despite its being 6 years after Oracle - poor show MS).
This is not a hazard, its a language feature. There was no mistake my Microsoft and correct use of the documentation would save most people. Merge is an advanced command as it rolls several previous commands in to one. Anyone using Merge should read all the docs and fully test that they understand prior to working on any code, even in development.
I think your explanation is good though and the it's always good to see a relatively new language feature being brought to the masses but when I read my email with this title, I questioned whether I might have missed an important feature of the statement so I had to read the article. In reality I simply wasted my time reading about a feature than I use very often in an article that added nothing new (to me).
Had the article been called
Introduction to using the Merge statement
Best practice when using the Merge statement
Common pitfalls when using the Merge statement
then I would not have even read it. Hazard indicates a bug to be avoided (to me).
David Bridge Technology Limited