Sorry Drache, my point was:
If you access a Wifi network that's encrypted, and don't specify the correct encryption on your client (No encryption counts as incorrect), then it'll associate just fine.
The problem, is that the data it transmits to/from the network will be nonsensical (since it's encrypted). This manifests itself to the user, as things just timing out, and not working. dhclient would indeed be discovering forever.
Pings would fail etc.
Seen it many times, and often people tell me they haven't got WEP setup on their routers, and it usually turns out they're mistaken