[MrManatee]

I've always interpreted "under-promise and over-deliver" as being about keeping your promises despite future unknowns. The simplest example I can think of: If you think some task will probably take 2 days, you say you'll do it in 3 days. If your original estimate was right, you'll be early, and others will just be pleasantly surprised (you over-delivered). If something unexpected comes up and your original estimate was too optimistic, you might still be able to do in the time you promised. Do this consistently, and you will get a reputation of delivering what you said you would.

Research article titles are descriptions of work already done, so I see them as "promises" of a different kind, and that's why the advice wouldn't apply. But if you said that you're going to write an article called "The Riemann hypothesis is true" before you have found a proof, then you're probably over-promising.

Campaign promises, on the other hand, are about future unknowns. I don't know much about campaigning, but I suspect politicians can get a way with over-promising better than most people, because the feedback cycle of elections is so slow.