People who received SEISS grants - ie the self employed - had to have submitted relevant tax returns before they were able to claim them. The first payments were made in May 2020 I think, or later, certainly not before. By the time they were paid the relevant tax returns had all been submitted so there was little scope for fraud. The self employed who were pissed off were the ones who'd fiddled their tax returns and so had low profits.
As has been mentioned in the past, there were thousands of self employed people who did not qualify for the grants.
But the loans were made by banks who would only do so if the govt backed them. At least a year ago accountants were reporting on their forums of clients who had taken the maximum loan and then spent on a car or some other such purchase. Some people took the money because it was there for the taking and not because they needed it. The banks didn't bother to do much checking because they would not lose out.
The self employed are declaring their SEISS grants on their tax returns and are paying income class and Class 4 NIC on them, assuming that their profits, including the grants, exceed the personal allowance.
The self employed are in for a big shock in the next year or so because the govt and HMRC have decided that they should do quarterly returns of their income and expenses in addition to the end of year tax returns. Many self employed are not very computer literate and either prepare hand written records or bags of receipts and statements.
The reason given for this is that businesses will have up to date information, the assumption being that they don't already know how well or badly they are doing.
The money that is being spent this would be far better spent on chasing the loan fraudsters.