Okay, I have no idea why this is being stated here: "Anecdotes are nice, but the debit card was not a Christmas card"

What does that have to do with Doing Something about this?

Let's review your Due Diligence: You get the client to tell you what they know, and if they did not "do the work" to investigate, you do it. Then, If there is every indication their stimulus for 2020 is "out there" you don't claim the credit. If they never get the Card or Check, and you confirmed there was no direct deposit that they conveniently didn't recognize, you can get a replacement check or card. That was true for the first EIP, too.

But you won't know until someone checks the EIP Status and their Tax Account transcript.