  Suppose one wants to certify that a quantum channel is not
entanglement-breaking. I consider all four combinations of trusted and
untrusted devices at the input and output of the channel, finding that the most
interesting is a trusted preparation device at the input and an untrusted
measurement device at the output. This provides a time-like analogue of
EPR-steering, which turns out to reduce to the problem of joint measurability,
connecting these concepts in a different way to other recent work. I suggest a
few applications of this connection, such as a resource theory of
incompatibility. This perspective also sheds light on why the BB84 key
distribution protocol can be secure even with an untrusted measuring device,
leading to an uncertainty relation for arbitrary pairs of ensembles.
