Sure, perhaps they won't use it for training, but the fear is they would use it for corporate espionage, market research, etc. Compared to training, this would

Sure, perhaps they won't use it for training, but the fear is they would use it for corporate espionage, market research, etc. Compared to training, this would be both more useful and much easier to keep deniable / under wraps. I've had previous employers that were highly concerned about far more innocuous data leaking to competitors, e.g. autocomplete search terms. This means that a Copilot installation at any company that competes (or might compete) with MS should be considered a security breach, IMO. Given Microsoft's presence in so many markets, in general I think it would be foolish to risk this at any company.