There has been a huge influx of passport available for sale on the Dark Web.
Also have seen posts where people are being accused of double entry into ICO's because the scammers used their passport information prior to them getting signed up.
Ohh. I am afraid of this issue a lot. These docs could be used in some money laundering things and this could cause a big problems for simple people or investors. Thus, today we have a trend for KYC ICOs that could solve this problem in the future.
But the best way is just to be carefull with scammy ICOs and at least to review partners of ICO project that perform KYC.