For the consumer, the most prudent approach is to rely on official carrier lookup tools where available or reputable paid services that offer refunds for incorrect data. Users should be wary of any site offering free "unlocks" or "cleaning" services, as these are vectors for fraud and malware. As Apple tightens API security, the availability of accurate third-party IMEI data may diminish, potentially pushing the market toward official verification methods.
This is the ultimate trap. Even if the carrier says the phone is clean, the previous owner might still have "Find My iPhone" enabled. iphone imei checker online