A node will indicate a spoof if it detects another radio using the same SSID and MAC Address (spoofed).
When a Spoof is seen, it will appear in Monitor > Air Marshal on the Dashboard (Figure 1).
Figure 1. Viewing spoofs on the Air Marshal page.
Spoofs cannot be contained or mitigated the same way a rogue or other SSID because you would be containing the Meraki network SSID as well. The only way to deal with a spoof is through a "Boots on the ground" approach.
1. Start by determining which of the Access Points is being spoofed. The affected AP's MAC address can be seen under the spoof section of Monitor > Air Marshal on Dashboard (Figure 2).
Figure 2. Spoof alert reported on Dashboard.
2. When ready, Disable the particular AP being spoofed. Then, using a WI-FI scanner (such as inSSIDer) measure the signal strength of the SSID(Figure 3) and determine where it is strongest. This will require taking various strength measurements from multiple locations. This process will give a good idea of where the Spoofing device is located so appropriate actions can be taken to disconnect the device.
Figure 3. Using inSSIDer to locate the source of the spoof.