Recently at work, I have been asked to interview some candidates that would potentially join the team that I am part of. As part of any technical interview for a software development position, a list of questions allows you to get an idea of the level of knowledge that the candidate has. Additionally, there is a growing trend of conducting live coding or fizzbuzz exercises, there are ongoing debates about the usefulness or fairness of doing such exercises but personally I feel that is it is a good way to asses the ability that the candidate has to find the solution for a problem while handling the pressure of an interview.
That being said, I do believe that the exercise should be simple enough so it is possible for the right candidate to be successful, for me the goal is get an idea of the way of thinking of the interviewed rather than marking it impossible to solve in the given time. Being that most of us software engineers use Google very frequently to look up documentation and even find solutions for the specific problem we are facing in Stack Overflow, it seems unfair to expect the candidate to know every language or framework API by heart. On the other hand, if the candidate is allowed to use Google while completing the exercise, there is a possibility (more so if you happen to choose a very common exercise) that he or she would look for the actual answer of the assignment instead of looking up tools for solving it.