Please see this blog for more details.
Essentially, the idea is to set up pre-configured containers so that event participants can directly log in and use Azure CLI without needing to install or configure anything. As shown in the following screenshot, all the participant needs to do is to ssh into the VM, and use start-cli to launch a new Docker container with Azure CLI pre-installed and pre-configured.
Because we can host many Docker containers on a single VM, each participant will have her own private session. Moreover, you can also set up multiple subscriptions, and the container will randomly pick one upon start (unless you specify one by the --evn SUBSCRIPTION parameter) so that a large audience can be distributed to multiple subscriptions.