IANAL, but I am an Android programmer. This kind of language exists in multiple other places in the Android docs for things that are more clearly suggestions.

IANAL, but I am an Android programmer. This kind of language exists in multiple other places in the Android docs for things that are more clearly suggestions. There's not enough consistency, plain and simple, but in the absence of clear "this is a requirement to be in the Play store" language, I absolutely, 100% interpret this as a guideline. These are "should" and "should not" things, and things which you obviously must do to meet the guidelines are mentioned. To be clear about ads, you must be clear about ads, and you should be clear about ads. Besides, they can already pull your app for basically any reason. This is just additional buffer, and it's something very few apps do, which includes e.g. Youtube which includes no such EULA when you launch it, no "opt in", it just shows ads on videos when they deem it valuable.