This thread is linked in #6 above. Here it is again.
viewtopic.php?f=8&t=515. The thread discusses constructive receipt. It's better to write a check* and then another one back. But if it's not done, I'd personally still claim it. It's not a shoo-in, but I'd argue IRS would be inconsistent to treat it as wages subject to withholding and payroll taxes but not for income tax deductin purposes. One of the posts in the linked thread says the poster would not rely on it. I agree documentation and checks would be ideal, but it's not always an ideal world.
*Although the Supreme Court points out that
a transaction is to be given its tax effect in accord with what actually occurred and not in accord with what might have occurred.
https://caselaw.findlaw.com/us-supreme- ... 9/569.html
How is it legit to deduct unpaid accrued expenses on the cash basis?. By arguing constructive receipt.