The organization I work for has site wide unsecured wifi, however to get access to it you have to supply your devices mac address to IT. Is this a secure method to prevent people from being able to packet sniff (or similar)? It is my understanding that it is not but IT are confident it is.
To give a bit of context to the sort of security needed, the organization I work for is large and very prominent. In addition the Wi-Fi is not just for work, as many employees live on site and use it, as well as there being multiple hotels on site that use it.