I've  read some great replies  and opinions  from people and truly I've come to raise that no matter how correct we might be, there is always a genuine defense against your opinion  and that's one thing the forum has made me realize.
Well from my personal opinion, I think it is good to attend these seminars especially  if it is legalized in your country but if its not,  then I wouldn't advice  you to go to such gatherings as there is always no form of safety guaranty just incase the government or security agencies catch up on you guys.
In a country  like mine, I wouldn't dare to attend  these seminars and I wouldn't also advice anyone to attend but rather make use of the knowledge  we get from the internet.