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Z is. In general, it would be a good site with a search by addresses with a crazy net. Why not? Anyone who wants to share can do it.
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It has been invented long ago.
They usually draw a special symbol on the wall, where the signal, password for network access and channel bandwidth are better captured.

Conditional indications :
picture "Circle"-Closed node.On top is written SSID.
The drawing "two semicircles deployed in different directions-type of such )( "-open point.Over-SSID,down-speed.
Circle with the letter W inside"-WEP point.Over-SSID+access contact,down-speed.

Show them, let them know.