The guests had to keep the task going to the finish without being found out, Thats why BB told Brevington they couldn't just drop it and let him explain what was really going on otherwise they'd forfeit the whole task.
And thats also how you could see they still had to be difficult but they were trying to rein it in a bit at dinner as to a) not trigger them any further as tensions was already at breaking point, but also b) after the meltdown The staff had displayed, the guests still carrying on as they were would've probably looked suss AF bro and risked the task. lol
Although they could've perhaps swung it as Bruce and Holly getting a personal penalty or taking a cut away from the luxury budget overall for not playing it out, as if it was a real task they would've failed it flat out, but with this particular one the main pass/fail metric was the secret task that everything hinged on succeeding (also with BB mentioning it was the guests behaviour being judged as sufficient enough I guess if Holly and Bruce still did everything they were meant to but ragequit temporarily and break the (fake) task rules, but I dunno.