Single sign-on restrictions now enforced.
UPDATE: JANUARY 6, 2015
By popular request...
We have built in a single sign-on interface which only allows users to have one consecutive session open on any device. This is to assist in preventing cheating or sharing during exams. Users attempting to sign on from multiple devices will be automatically logged out of older sessions before being signed in on the new device.
For example, you cannot complete an exam, open your answers on a desktop computer, then retake the exam on your smartphone or tablet with the exam questions/answers open.