That might happen at some third world countries but in general evac'ed passengers are kept in quarantine until they have given information about what happpened. They are well cared for and those who have lost passports are provided with emergency travel documents based on the identity documents presented at booking or boarding. Consequential losses ( prolonged car parking fees etc ) are almost always covered by the air line or theri insurers.I would still rather take my passport. money and car keys because once you are off the plane you are left to fend for yourself.
The evacuation trials at Cranfield make it clear that one passsenger dithering a few seconds to collect a bag disrupts the flow to the emergency exits and significantly increases the risk of other passengers not being able to get out before they are over come by fumes and die on board.