Not just Singapore , a lot of other airports do this as well ,as other comments have pointed out. This isn't the norm in the UK unfortunately. The reason boils

Not just Singapore , a lot of other airports do this as well ,as other comments have pointed out. This isn't the norm in the UK unfortunately. The reason boils down to staffing on the other end to check the token and to handover the tray. Token and staffing would mean added cost and liability - not something an outsourced security vendor or another government department agency would be willing to foot the bill for.