The Reporting API is distinct from most core, existing browser functionality in that it principally benefits the site operator. It is asking web users to help the website identify errors and problems in the site owner's application (e.g. to have users serve as debugging and monitoring agents for the site owners).

This is useful to site owners, who will can offload monitoring costs to users and be notified of conditions the site owner might not anticipate. It may be useful for web users, as a group (the indirect upside of bugs and attacks being identified sooner; the downsides of bearing the burden of monitoring the site on behalf of the site, and possible privacy concerns). It is very unlikely to be useful, at the margin, for any single web user.

The Reporting API therefor should be treated as a benefit the client provides to the website; it should require explicit opting in on the part of the client, globally, and with per-origin exceptions, though a permissions like system.