Normally it is happening on visit visas. It once happened to a close friend of mine. He brought his brother in law on visit visa under his sponsorship. That guy tried to get a job in qatar but in vain. He overstayed and did not renew his visa. He got a job somewhere and told my friend that his passport is with his sponsor who is getting his RP stamped and is in the immigration for extending his stay. My friend believed it till the Search and Found Department approached the company of my friend asking for him. My friend went with the PRO to the Officer in-charge of the Search and Found Dept. who told them that there is a warrant against my friend to catch him and deport him. My friend asked his brother in law about the situation who replied that his would be sponsor has lost his Passport (as per my knowledge that guy was a Govt. Employee and he destroyed the Passport and paid the fine in the immigration to save himself). My friend was lucky to be in a strong company who got the case cleared through strong connections in the Ministry. That guy approached the Embassy and arranged for a travel document and was deported within 3 days.