My app was randomly rejected for this reason on a recent version. That version did not change the functionality around signing up or feature restriction what-so-ever. It only had bug fixes in it. Every single version previous to that had the exact same functionality. This rule is obviously very arbitrary and up to the reviewer to decide that a feature "doesn't require account access." Apple needs to clearly define this rule, and give that definition to their reviewers so that they are reviewing apps consistently. When apps are not reviewed consistently, the whole purpose of the app review becomes pointless. Wether or not an app gets approved mainly depends on WHO reviews your app, and not on the functionality of the app.