Howard, I've thought about this as well and share similar concerns.
I'm expecting that the overwhelming majority of my clients do not have that notice anymore.
It would have been nice if the IRS would have issued some kind of notice or 1099 in January, but that's wishful thinking.
I've been mulling this: asking in the organizer if the client received an EIP/stimulus payment, then "if yes", asking them to upload either their IRS notice OR their relevant bank statement with the EIP/stimulus payment line item highlighted.
Yes, it is tedious, but I think we need to get this right, or else clients will be getting adjustment notices left, right, and center.