I have asked the developers and we are sorry but we cannot give prizes to guest accounts. This involves mostly you Ninja and YE1 I think as well. The reason behind this is that guest accounts are not permanent and you might lose the gems you earned in an instant. Please consider making an account (if you do so inform me about the new username and I will change it).
Obviously you are allowed to play the tournament on the guest account, but in case you get into the prize ranks, you will NOT be rewarded.