Why would anyone want their diplomacy interrupted, even as the one being affected? It’s not like diplomacy is some evil spell. A successful diplomacy check means you were able to have small talk, relate, and do all the normal things strangers do to put each other at ease. You don’t “defend” against diplomacy!
Imagine trying to agree on a treaty with some jester interrupting every 54 seconds…
They never really went into detail, their whole argument was that if you wanted to use Diplomacy, you did so by default at a -10 penalty (for doing it ‘rushed’), or it would guaranteed fail, for the above reason. :(
Why a -10? That seems arbitrary in 5e that almost does nothing with incremental modifiers.
This was pre-5e; we were playing 3.5e, where that’s actually an official thing you can do:
Changing others’ attitudes with Diplomacy generally takes at least 1 full minute (10 consecutive full-round actions). In some situations, this time requirement may greatly increase. A rushed Diplomacy check can be made as a full-round action, but you take a -10 penalty on the check.
