Email Protection Basics in Microsoft 365: Spam & Phish

Thanks for your question, PeterForster! Our telemetry shows customers are actively using Advanced Spam Filter controls, so it is about the administrators' control and customization. If you choose more aggressive spam filtering, test carefully and use these settings accordingly; in case of false positives, look out for X-CustomSpam in the message headers. Microsoft defaults are all 'Off', which is sufficient for most customers.