I reread the rules, and I take back my words; according to the rules, he wasn't allowed to just go for it blindly. It's absurd. On the other hand, he might have had evidence, known only to him, that he could have presented in case of a challenge. Or maybe he just had a gut feeling that his opponent had succeeded – why not? In short, this rule also needs to be more specific.
Зима 2011-12.