... wonder no longer. It is on me. In response to a personal email from a journal editor I wrote:
I foolishly accepted about a thousand review assignments this summer. I've been late with all of them but am slowly digging out. I'm writing one for [journal name redacted] today and will begin reading the [journal name redacted] paper tonight. I should be finished in about a week. Very sorry for the delay and thanks for your patience.
In response to the kind reply I wrote:
I have hypothetical bias with my time budget.
I need a certainty follow-up question after I accept the assignment: "how sure are you that you can actually complete the review by the deadline?" I would be forced to answer: not sure at all.
A cheap talk script might work. Or an oath. Or a journal editor might just throw up his/her hands in exasperation: "I've gone from dubious to hopeless about these stated preference expressions of willingness to review!"