Sanctioned jurisdiction blocking
OFAC and EU restrictive measures impose strict liability. 71M people in sanctioned jurisdictions live within 100 km of a border with a non-sanctioned territory. 168M people in sanctioned jurisdictions live within 200 km of a border with a non-sanctioned territory. But IP databases disagree on the same address by an average of 620 km, so an IP lookup will easily place well over a hundred million individuals in sanctioned jurisdictions in the wrong (unsanctioned) country.
Octet attests directly to the device's presence relative to the named polygon set. A regulator asking for evidence gets a signed predicate, not an IP heuristic.