Re: Holland was clearly making a point..
If sending to more than three people (or more than 1 domain) then any decent client should default to BCC
In my organization we frequently have triparty exchanges where everyone could contribute. BCC-ing everyone would just make it impossible for people to know who they need to reply to. But I agree there should be a soft or hard cap on the number of recipients, above 10 you can be almost sure that some people don't belong in a discussion.