“Automatic payments are guaranteed only to those whose information is already in the computers at the Internal Revenue Service or the Social Security Administration. Everyone else must follow instructions posted by the I.R.S., which says many low-income people and others who aren’t usually required to file tax returns will need to do so if they want their payments.
“Until an abrupt reversal on Wednesday night, the guidance also applied to Social Security recipients who did not submit tax returns. That had been a surprise to policy experts and advocates for seniors, because the legislation signed by President Trump gave the Treasury explicit permission to use Social Security databases — and the payment information they contain — to push payments to people automatically, without their needing to do anything else.
“The Treasury Department backtracked on Wednesday and said Social Security beneficiaries who did not typically file returns would receive their payments automatically after all.”
(https://www.nytimes.com/2020/04/01/business/coronavirus-stimulus-social-security.html)