GET /api/activity/reports/risk/member/

Return one member's advisory risk score and tier with the per-cell (category, severity, action) points and per-category subtotals behind it, over the same fixed rolling 30 days as the member list. A member with no scored security events in the window (info events score nothing) is not_scored with a null score, and so is a service account, which is never scored. With percentiles=true, percentiles ranks the member against the organization's tracked members (any activity in the window) and each of their groups; a population under five tracked members has a null percentile. Without it, or for a member who is not scored, percentiles is null. Restricted to organization admins/managers or activity & security report viewers, and gated by both the activity-tracking and risk-scoring flags.