I wish this post was more explicit on whether it was restricted due to a security issue or because it allows paywalls to be bypassed.

at face value id expect two things just due to the nature of a paywall bypass:

--Add-ons and their content must conform to the laws of the United States. (Add-ons that violate or have content that violates the law in other jurisdictions may also be removed or have access limited.)

--Add-ons with the sole purpose of promoting, installing, loading or launching an outside website, application or add-on are not permitted.