While there may well be good reasons to MitM HTTPS on a corporate network, the case isn't quite so clear for secretly doing so. IIRC chrome disables altogether certificate pin violation notifications if the offending certificate is locally installed. While it probably is the right move to forgo the giant security warning in that case, I don't see why they can't use an "orange light" type indicator and in the popup explain corporate monitoring (with a further note that if you aren't on an institutional computer you probably have a virus). While corporate IT departments could recompile chromium sans message, or just ban chrome altogether, why make it easy for them?
If you are using corporate hardware it should not really be secret that your traffic is being man in the middled, this should be assumed. I think it makes sense for a corporation to be able to whitelist their certificate to make intermediate network devices appear as trusted, because they are. I do agree that having a little asterisk or something for the lock ice to indicate that you are using a certificate that falls outside of the default trust store could be beneficial.
The stuff I work with has the option to pop up a warning/comfort page to explain the practice/policies etc every N hours - seems to be a good thing to use.
