Trying to do some work for the Mystery Hunt which starts on Friday at noon, and the wireless at MIT keeps deauthenticating me for reason 1. (Which apparently is the dreaded "unknown reason for deauthentication".) Reassociating makes everything work again. Fast, hack solution:

 while sleep 1s; do
  if iwconfig wireless |grep -q "ESSID:off"; then
    iwconfig wireless essid "MIT GUEST";
    echo "reset wireless";

and I'm back at work with relatively continuous network connectivity.