May a Marktplaats buyer or seller request my ID?

A Marktplaats or Vinted transaction is no contract where ID inspection is proportionate. Private buyer/seller has NO basis for ID data (GDPR Art. 6 + Wabb for BSN). Almost always a red flag: ID request on Marktplaats is typically fraud. Common scams: "for shipping insurance we need your ID", "for the NS payment your ID needs verification", "I only buy from people with verified ID". What to do? (1) Refuse. (2) Ask why — on vague "just to be sure" = scam. (3) Report profile to Marktplaats as suspicious. (4) On financial impact: police report + Fraudehelpdesk + bank. (5) On suspected BSN misuse: RvIG report. When IS ID request legitimate? (a) Licensed intermediary (official car dealer at car sale — transfer form requests ID). (b) Statutorily required transactions (notarial deed). (c) Especially large amounts (>€10k) via Wwft trajectory — but happens via bank/notary, not via buyer themselves. Tip: Marktplaats has improved verification via iDIN + Acquaint since 2024 — no ID exchange between parties needed.