A person can create an account because they want one thing and accidentally volunteer for six other things along the way.
That is the power of defaults.
Registration already asks for attention: email address, password, name, terms, perhaps a phone number and verification code. Marketing preferences can be tucked into that flow as another checkbox the user barely notices.
If the box is already checked, doing nothing becomes agreement.
Defaults manufacture participation cheaply
From the company’s perspective, the attraction is obvious.
Every new account becomes a potential marketing contact without requiring a second decision.
The user may believe they are creating an account to buy a product, access software, join a forum, or receive a receipt. The system can interpret the same moment as permission for newsletters, product announcements, partner offers, SMS, push notifications, or promotional profiling.
That difference between purpose and default is where the friction begins.
Mailchimp’s current GDPR guidance states that when consent is relied upon for EU users, it must be freely given, specific, informed, and unambiguous. Its popup-form instructions specifically say consent boxes should not be pre-checked. See Mailchimp’s GDPR form guidance and its overview of GDPR consent.
That is a jurisdiction-specific legal framework, not a universal rule for every signup form on Earth.
But it illustrates a useful design principle: marketing agreement should look like a choice rather than residue left behind by account creation.
Clear enrollment exposes the trade
A transparent form makes several things visible.
What messages will be sent? Through which channels? How often? Is the marketing optional? Are third parties involved? Can the person create the account without joining the promotional list?
Those questions matter because silence during registration is easy to exploit.
The user is focused on getting through the door. The marketer is focused on preserving a future channel back to that user.
Spam Empires industrialize that tiny mismatch.
One preselected box does not look dramatic.
Multiply it across millions of registrations and it becomes a machine that converts inertia into recurring attention.