Aiding and abetting, or as S.C. law calls it, accessory, means that someone helped another person commit a crime.  According to S.C. Code Section 16-1-40, if a person is found guilty of being an accessory to a felony, he or she will face the same punishment as the person that committed the felony. 

So, in the situation where a person is a getaway driver for an armed robbery, the driver will face the same penalty as the person who actually went in and robbed the bank.