Your thread title is a bit misleading.
I think you are referring to 802.1x, one of the methods used to secure WLAN access points. This one uses EAP, but others are also in use such as LEAP and even WEP. There is no 802.11x*.
Back on topic now.
What I would do is use the command line NET SEND and then point that to any machine I can find on that WLAN. Unless they have disabled the Messenger service, they should get that as a popup message. No intrusion aside from the WLAN access can then be blamed on you.
*IEEE Std 802.11, 802.11a, 802.11b, 802.11b-Cor1, 802.11d, 802.11e, 802.11f, 802.11g, 802.11h, 802.11i, 802.11j, 802.11k, 802.11m, and 802.11n are trademarks of the IEEE.
All other names or product names are the trademarks, service marks or registered trademarks of their respective holders.