I have been having the same problem - Roku 2 is broadcasting beacons even though it is on Wired mode. I was able to fix it by doing two things:
# Use Logitech Harmony remote - if you configure it for Roku, then it uses the old IR codes
# Go into the secret menu (Home 5x, FF, down, Rew, down, FF) and then select secret Wireless options, there is an option for “P2P Stop” - it tells you this disables RF remote - I did that.
# Checked Wireshark - no more beacons!