Nothing is more likely to breed suspicion amongst colleagues than the regular use of BCC: or blind copy on emails. It is a curse on organisations and I blame Microsoft (and the others) for ever inventing the feature in the first place.
The most obvious problem that I have fallen foul of time and time again is when you receive an email by BCC: but don't realise, so you just Reply All: Oh yes, been there, done that, got the t-shirt. However at least you are not the one who will be embarrassed. The Blind Copier cops the blame and looks like a shifty so and so for sending a BCC: in the first place.
The real problem is that if someone is a regular Blind Copier and you are the recipient of these, then you must assume that any emails they send to you are probably being blind copied to someone else. Both scenarios leave you in an awkward place.
If you have been BCC:d on something, then do you know about it or don't you? When you meet the people who were sent the email, can you engage in the conversation about the issue in the email or do you have to play dumb? What if they somehow know that you know, but you don't let on that you know? Then you look sneakier than ever, through no fault of your own.
Equally when you receive an email from a Blind Copier you are left wondering who was BCC:d on your email. When you meet your colleages, were they BCC:d and they are just not letting on or do they really not know?
And what about the Blind Copier? Did they BCC: you because you need to know this information? If so, why is it so important that other people don't know that you know? Or are they just showing you how tough they are being about some issue, a sort of cheeky wink at a friend as they pile in to do battle, leaving you grinning complicitly on the sidelines.
Oh the permutations are endless. But any way you look at it, BCC:ing is a bad idea. If you have something to tell people, tell them. If you don't, don't. Creating these wheels within wheels risks a climate of suspicion that doesn't do anyone any favours.
I never use BCC: myself. I get lost in the complexity of who I've told things and what I've told them at the best of times, let alone whether I've told them something secretly, so I stick to plain, open emails. If I want something kept confidential, I say "Please keep confidential". In fact I generally try to write any email on the assumption that I wouldn't die of embarrasement if its contents were posted on the office noticeboard.
And I think I will revert back to my hardline BCC: response strategy. If anyone BCC:s me I will immediately Reply All: so that everyone knows that I know and I don't have to pretend about what I've been told. If that causes the Blind Copier some embarrassement, well my guess is that it will only be the once. I doubt they will BCC: me again. If they do, I will simply post the email here for all of you to read :)