Fine-grained warrant canaries

A warrant canary is a method for informing one's users that no government subpoenas or gag orders have been received. It relies on the fact that the laws forcing silence about such matters cannot actually compel a person or entity to actively lie. This slight modification of the warrant canary would make it much more useful.

The site, business, or other entity publishing the canary would simply publish a whole table of canaries, listing each concerned customer or other stakeholder. Upon receiving a request related to John the rest of the table would still be published, but John's name would be removed. Obviously customers may want the canary to use a pseudonym instead of their real names.