On Thu 2016-01-14 16:20:59 -0500, Daniel Kahn Gillmor wrote:
> This suggests that if i include a bogus message-id in my References:
> list for any mail i send to a notmuch user, then access to their
> database will let me tell whether they ever saw it or not, regardless of
> whether they deleted the message.

The script below demonstrates the problem.

before the message is added and removed, delve -a shows:

----------------------
All terms in database:
----------------------

but afterward, it shows:

----------------------
All terms in database: G0000000000000001 Qno-such-message@example.org Tghost XDDIRENTRY2:new XDIRECTORY XDIRECTORYnew
----------------------

    --dkg