For a very long time, wifi at work was a big no-no, simply because the IT admins considered it too insecure. Now suddenly it's quite common. What changed? My theory is that businesses started buying iPhone plans for their employees, which come with data allowances and excess usage charges. So when the data allowance runs out, it costs the business a lot. The best way to get around that, at least while employees are at the office, is to set up a wifi access point and direct the iPhone internet traffic through there, piggybacking it on the existing internet connection. Money and convenience overrides security yet again.
Mokalus of Borg
PS - That's usually how we get into trouble.
PPS - But in fact, it probably wasn't that secure before or after wifi.