First of all; I am totally new to Sonos and have never owned a Sonos product before. After reading good reviews, I was thinking of getting 3x Sonos One for a hotel lobby. We are aiming to just play relaxing background music so I thought they would be perfect to syncronize them through some different rooms.

However, I am a bit concerned that guests might be able to connect to the speakers and play their own music. If I establish a second WiFi and connect the Sonos to them, and disable Alexa/Google Assistant, will that be enough to avoid people from connecting, or can they still connect through cast/airplay?