I completely disagree, this statement is complimenting them for screwing up, (in a way)
I personally would email the entire office, and state that these standards (of xrefing) are there for a reason, and if you have problems you better ask someone a solution, because unless someone instructs you to bind/explode an external reference, you better not do it or you will be fired. Period. End of story. I would not say the persons name, either. Is there an in-house architectural department? Why couldn't he just go ask someone to fix something... if not, then the person in charge of maintaining xref'd files should be the person to find out what the problem is, (was it a wrong background?) and coordinate with the Arch on the job to make the necessary corrections! But first and foremost, he or she was obviously wrong for doing this without communicating with other TEAM MEMBERS. If he is old school, that is not your companies fault if he is unwilling to learn. If that is the case, I say kick the old dog to the curb if he can't learn a new trick.