The first thing a good Network Security consultant will tell you is not to include WiFi in your office solution. WiFi should NOT be the primary source for network connectivity; 802.11x is unequivocal to wireline in the arenas of speed, reliability and security.
Now, with that said. WiFi as a mobility tool is a necessary evil for workflow and at times can't be avoided. What's crazy is to think that a firm would allow a personal device into their network albeit a smart phone, tablet or laptop. What happens if that device has proprietary and/or confidential work product on it and then gets left at the local coffee shop or stolen? What happens if that device brings a virus or malware into the network?
Firms should NOT allow personal devices into the LAN. If they do, there needs to be some sort of policy to allow the firm to protect its digital assets and maintain the integrity of the network security protocols.
I can appreciate people wanting to connect up there personal devices in the network, but the employer better make dang sure he can control those devices and provide some parameters for them to be operated in.
Handing out the WiFi password is never a good idea for personal devices. If those devices just need Internet access, consider a DMZ or isolated network not on the same subnet as the main 'LAN'. Some vendors call this the 'guest' network (this is a good idea). I’m not sure allowing smart phones onto your WiFi networks should ever be permitted. What would the smart phone be doing other than checking personal Facebook, Twitter, Instagram and streaming Pandora or Spotify? AND, Not to mention these activities all take Internet bandwidth, which last time I checked, was not infinite. Better to keep that bandwidth open for SaaS applications and VoIP services.
If the employee is using a personal device then, as aforementioned, there needs to be some safeguard as how to get the data off the device if it becomes compromised. There needs to be a conversation about how WiFi is handled. There needs to be policy and producers adapted so there is a VERY clear understanding about the rules and consequences of WiFi use.
If mobility in the workplace is going to advance then we must talk about how to manage those moving targets and safeguard them.