I received a Battlenet message from an account I don’t recognize and they were asking about a specific addon I use (Details!).
They aren’t on my friends list and I’m not a member of any Battlenet chat groups. How were they able to send a message to my Battlenet account?
That is very strange. Did you perhaps have them on your friends list at one point in the past? I know that saved chats can allow people to message even when not friended
Could be a friend of a friend, most of the time you can see who your friend is a friend to, and even invite and message ala facebook.
You can turn this off though, in Privacy/Social settings under account management.
I didn’t recognize the account name so I don’t think so.
I have only started playing again this summer after a 2 year hiatus and ‘Details!’ is a new addon for me so it was a bit weird for them to be specifically asking a question about that addon.
@Kozzae
Don’t think that is the case as I have a very small Battlenet friends list and I’m the only WoW player.
Would be weird that someone would message a friend of a friend and not bother to say "Hey I’m a friend of xxx…’
I did see that there was an option for “Private Text Chat” in the account Privacy settings. But that seems to be something related to Chat Groups which I don’t belong to. I did set it to ‘Friends Only’ now.
I do recall the BattleTag ID number they had was crazy long… like 12 numbers instead of the typical 4.
Thats odd but not too worrisome you can either a answer the question
B put them on ignore
C ask them how they know you.
If it was someone claiming to be a gm rember if you can report them there a fake.
They weren’t claiming to be a gm. I just closed the conversation. I figured it would be best not to interact with them.
It was a example.
It was understood 
If in doubt always just ignore it. Better to be safe