lol no? lower cert times still extend the root certificates that are already trusted. It is not a noticeable thing when browsing the web as a user.
A MITM cert would need to be manually trusted, which is a completely different thing.
I think their point is that a hypothetical connection-specific cert would make it difficult/impossible to compare your cert with anybody else to be able to find out that it happened. A CA could be backdoored but only “tapped” for some high-value target to diminish the chance of burning the access.
> I think their point is that a hypothetical connection-specific cert would make it difficult/impossible to compare your cert with anybody else to be able to find out that it happened.
This is already the case; CT doesn't rely on your specific served cert being comparable with others, but all certs for a domain being monitorable and auditable.
(This does, however, point to a current problem: more companies should be monitoring CT than are currently.)
Well, the cert can still be compared to what's in the CT Log for this purpose.