User blog comment:Bennlimos/HxH Questions & Thoughts Discussion 9/@comment-5780397-20141012102727

1) Most of them do, I think. Kurapika and Leorio found out about it, after all. They get hints while applying for jobs, so, since they are actually Hunters and not fools, they can investigate. But it might also be the Hunters who do not learn Nen become Temp Hunters. In this case, their number would be sizeable.

2) They might have done things by themselves after passing the exam, so the possibility they did not know Nen is not too far-fetched. But it might be that Canary was simply too strong for them (both Hisoka and Illumi killed scores of pro-Hunters before they could even signal their presence), or that they lacked battle-oriented abilities, although it is probably because Nen had not been introduced in the series at that time, so it wasn't shown in the fight.

3) You know when grandparents go to their granddaughter's dance recital? I think he just wanted to watch Illumi carry out such an important task. Else, he might have been watching over Kalluto.

4) He probably knows when an ability fades from his book. Nen users without their abilities won't enter a dangerous battle and either retire or change job. They might try to track Chrollo down, but with no success. Maybe he mutilates them so bad they end up in a coma.

5) Keep in mind that the Troupe is a group that would use a coin to settle disputes. They even refrain from revealing their abilities to each other. It is likely they made a rule to allow everyone freedom, which after all you could say is one of the peculiarities of the Spider: being able to do nearly whatever you want.

6) Mmh, tough one. I can't pick.

7) Retired, caged after the fall of the Mafia Dons (he worked for the underworld after all, and without his protectors he might have been arrested), or in a hospital due to Feitan's torture.