What vulnerabilities do maids risk as second cl citizens in Kuwait or Singapore?

There are very serious problems of physical abuse, ual abuse, denial of payment, refusal to provide time off, inadequate housing, and confinement to the home, and pport confiion in both of the places you mention. As non-citizens of extremely tightly controlled, tiny states, foreign maids risk having their complaints dismissed out-of-hand, or even being deported for daring to go to the police.