What's the difference between legally required suppression (e.g., unsubscribes) and operational suppression (e.g., bounces)?

Legally required suppression encompasses addresses you must exclude from marketing sends due to regulatory obligations. This includes people who have unsubscribed (honoring opt-outs is required by CAN-SPAM, CASL, GDPR, and other regulations) and addresses where sending would violate other legal requirements. Legally required suppression is non-negotiable. You ucannot send to these addresses regardless of business pressure, list import processes, or perceived opportunity. Failure to maintain and apply legally required suppression exposes you to regulatory penalties, lawsuits, and ESP enforcement.

Voluntary suppression includes addresses you choose to exclude for business, deliverability, or ethical reasons beyond what's legally required. Examples include hard bounces (continuing to send wastes resources and harms reputation), known spam traps (sending to them damages deliverability), competitors' addresses (some businesses exclude competitors from marketing lists), inactive subscribers (proactive suppression of long-term non-engagers), and addresses identified as risky through list hygiene services. Voluntary suppression is a business decision rather than a legal mandate, though neglecting it can indirectly create legal problems through poor deliverability and increased complaints.

The practical difference is in how you manage and potentially reverse suppressions. Legally required suppressions (unsubscribes) can only be removed through valid re-consent from the subscriber. You ucannot unilaterally decide to send to them again. Voluntary suppressions can potentially be reversed based on business decisions or changed circumstances. If uan address stops bouncing, you might test it again; if an inactive subscriber suddenly engages, they might return to active status. Your systems should distinguish between these suppression types so you know which addresses could potentially be re-activated and which are permanently off-limits until the subscriber themselves takes action. Legal suppression is a boundary you cannot cross; voluntary suppression is a guardrail you've chosen to install for your own protection.