If it was a hacking ploy, the network SSID would be exactly the same as yours and open - so that you would connect to it automatically (if they had stronger signal) and you wouldn't notice.
I often do this to my neighbours at weekends when they are playing youtube on their laptop or phone after 1am - basically clone their network (only one unique SSID allowed) and put a password - it stops them as they go out of signal and come back in and they've not ever figured it out. They just think the WiFi is broken again.
If I left it open, no password - they would connect and I would be able to perform a DNS reroute or man in the middle attack and monitor their net activity or other things that might be considered illegal - sure they might tap in my router IP and see connected devices - but it doesn't happen.
As a security analyst, I would consider that a network ID such as "bestfriend" has simply made a new "BestFriend".
If it was a real hacking ploy - it would be the exact same SSID and open network and you likely wouldn't notice as you reconnected to WiFi, as likley there is autoconnect to name.
It's a very old trick - take a laptop into a coffeeshop and DNS reroute from a wireless dongle to their login site - get people's traffic.
One reason why card readers often work off the WiFi and are hard-lined to the bank - it's too easy to MiM a Starbuck's network and another few seconds to watch the image cache of every device - hotels too, that use repeaters for extended WiFi.
Esp. in USA, where some hotels do not even have a password and are very tall.
Sniff that in a few seconds and even access the main desk machines or backoffice from a telephone, sometimes.
(I've had network names such as "I've seen you naked" and someone's changed theirs to "me too" and "I don't want to see you naked". Or sent messages - eg, "working shifts", so neighbours know that it's ok to party all night, but please don't wake me by knocking my door for a chat because I'll be asleep at 0800).