For public sector workers, yes their job is secure.

The 'no guarantee' part is the tenants for the investment property. But this is where the landlord must be wise to buy a property with excellent transport links and amenties (such as next to MRT and shopping mall), and landlord must not be too greedy. The rental has to follow the market rate, if it falls then rental must fall too to ensure the property is Always Always tenanted. If the investor is wise enough to buy good property and to charge a reasonable or attractive rent to the tenant, the risk is manageable.