User blog comment:Martialmaniac/Chrollo, that chatterbox/@comment-17259909-20160509205629/@comment-17259909-20160511010133

I don't recall him revealing his abilities to the Zoldycks. Zeno did most of the deductive work. And Chrollo was holding the bookmark when he explained Order Stamp. He doesn't necessarily have to explain the limitation that makes him reveal his abilities; just revealing the abilities should be restrictive enough.