Question for Office Types

[Citroënbender]

A modestly large local entity which we are engaged with as clients, has inadvertently shared almost 200 client email addresses by selecting CC instead of BCC on an informational email.

Definitely not their usual manner, they are big on discreetness and privacy. We aren’t particularly fussed, there is negligible risk ongoing other than perhaps nuisance emails from other recipients who haven’t locked down their own accounts so well (remember Plaxo and LinkedIn taking over peoples’ email address books).

What I’m curious about, is how would the employee of several years who made this mistake, typically be treated by an employer? Would they be given strong hints to leave, or just be called in for a chat with senior managers to see if there was any help needed?