To test, put your phone in airplane mode then turn on WiFi. If you're not blocked you will be able to force your phone onto the WiFi network.This is a really good question.
I enabled it a while ago but don't see the "AT&T Wi-Fi" status, then I realized I am at work. We cannot access personal Mail because the port is blocked, and now this likely isn't working for the same reason.
So much for getting phone coverage at work deep inside a building. Sucks.