Some thoughts on permission

A lot of email marketing best practices center around getting permission to send email to recipients. A lot of anti-spammers argue that the issue is consent not content. Both groups seem to agree that permission is important, but more often than not they disagree about what constitutes permission.
For some the only acceptable permission is round trip confirmation, also known as confirmed opt-in or double opt-in.
For others making a purchase constitutes permission to send mail.
For still others checking or unchecking a box on a signup page is sufficient permission.
I don’t think there is a global, over arching, single form of permission. I think context and agreement matters. I think permission is really about both sides of the transaction knowing what the transaction is. Double opt-in, single opt-in, check the box to opt-out area all valid ways to collect permission. Dishonest marketers can, and do, use all of these ways to collect email addresses.
But while dishonest marketers may adhere to all of the letters of the best practice recommendations, they purposely make the wording and explanation of check boxes and what happens when confusing. I do believe some people make the choices deliberately confusing to increase the number of addresses that have opted in. Does everyone? Of course not. But there are certainly marketers who deliberately set out to make their opt-ins as confusing as possible.
This is why I think permission is meaningless without the context of the transaction. What did the address collector tell the recipient would happen with their email address? What did the address giver understand would happen with their email address? Do these two things match? If the two perceptions agree then I am satisfied there is permission. If the expectations don’t match, then I’m not sure there is permission involved.
What are your thoughts on permission?