Can't scrap sponsorship system unless infrastructure is in place to (a) mutually enforce contracts including workers getting paid and treated as promised when fulfilling their obligations to employer, which means the equivalent of an employee rights agency, (sorta like Brit and jack says) and (b) immigration rules aligned so those without jobs don't just show up and troll about for months on end and create a permanent underclass and add additional costs to the country (as blue points out). Qatar is blessed to have very little of the latter and all that comes with it in terms of crime, resentment, etc.

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A wise young crackpot knows no fear - Ian Dury.