But you are dismissing a perfectly legitimate use. I had no idea there even existed an "Other" folder and when I did find out, there were a half dozen legitimate mails from longlost friends of various types.
I can see the privacy concern here but to call the above "spin" is being ignorant to a very legitimate use case. The $1/msg seems like an interesting compromise - if someone legitimate really wanted to reach me, they probably wouldn't mind spending a dollar.