It is pretty common to see someone robbing a bank with a mask on. The person obviously does not want people to identify them. In Florida, penalties can actually be increased if you wear a mask during the commission of a crime.
If you commit a felony or misdemeanor, the level of that crime will be reclassified to the next higher degree if while committing the crime, you were wearing a hood, mask, or other device that concealed your identity. If you commit a second degree misdemeanor, it will be raised to a first. If you commit a first degree misdemeanor while covered, the crime is reclassified as a third degree felony. The same goes with third degree felonies and second degree felonies.