implied consent

Implied consent is an assumption of permission to do something that is inferred from an individual's actions rather than explicitly provided. 

In the context of commercial email and text messages, for example, implied consent may be assumed by the senders because the recipient purchased a product from the sender's website or volunteered with the sender's charitable organization recently. 

Implied consent is a fairly broadly-applied legal concept. Here are a few examples in other contexts:

• Drivers are assumed to consent to blood alcohol testing. The inference is that the driver understands that driving under the influence is illegal and that they may be subject to testing.
• If an individual rolls up their sleeve for an injection or to have their blood pressure tested, they are assumed to have given consent and have no legal grounds to claim it was done against their will.
• In court, if an individual fails to object to a line of questioning within a reasonable time span, implied consent is assumed and they will not be able to object to it in the future.

Implied consent contrasts with express consent, which is explicit verbal or written permission. Anti-spam regulations, such as CAN-SPAM and CASL, differentiate between implied consent and express consent. As a rule, email senders have much greater latitude if recipients have explicitly consented to receive their mailings.

See also: permission marketing, opt-in email, unsolicited bulk email (UBE)