Most of what I know about the Marriott WIFI blocking was learned from a thread on NANOG (North American Network Operators Group). I don’t run a network but I find some of the banter on that list fascinating.
Just for completeness, here is what I posted to the google+ thread:
The 802.11 WIFI protocol has a bug where the de-authentication packet is not authenticated. That allows anyone to forge a packet with a different wireless client’s MAC address and have their upstream access point tear down the connection. NANOG had a long thread on this. One interesting thing that came out of the NANOG discussion is that some big-name AP equipment even has provisions for automatically generating these forged de-authentication packets.
Personally I think people should be using a USB or Ethernet cable to tether their computers to their cell phones or hotspots. That would keep Marriotts grubby hands off of the connection.