Where opt out is possible and easy the government should not manage the risk - because it could create moral hazard (i.e. increase the incentives that individuals have to take risks). However, this clearly has ethical and equity implications, particularly when ability to pay is a factor behind the failure to contribute (e.g. provide no assistance to those without insurance). In practice where physical excludability is possible (e.g. deny access to a clean water source), societies will need to make judgements about whether the poor should be protected.