If we look at the damage, it is for some people to be able to use the phone in the classroom have to sneak a game or chat with friends in the program, no fan chat.
If we look at the downside it is for some people to use the phone in the classroom, it will secretly playing games or chatting with friends, it's not chat applications.
If we look to the disadvantages it is for someone that can use the phone in the class, it จะแอบ play games or talking to fans or friends in a chat program.