ehrr
yes and no
I pretty sure there is some law that says something about
"illegally consuming bandwidth" without a contract from the network owner...
So DCHP in place and lack of WEPor other security measures would probably not be viewed upon I a court of law as
"I should get out of jail -free card"
-cause the didn't have any security in place your honour.
-That's why I used up all there bandwidth to upload and download my ripped DVD movies...

Reason ? Corp X co-workers was probably "tricked" by the slick WLAN salesmen (just look at the ads) most probably without the knowledge of what they were doing, and the authorization from proper responsibilities from corp X.
-ehr Bob, haven't we got a FW I place so we are secure...?
-Yes Joe, lets play with this new WLAN stuff...

We all know that average Joe at Corp X cant probably spell to security...But there is still laws that most probably will protect that stupidity.

So you have a WLAN honey pot -any interesting findings that you want to share ?