I know someone who wrote numerous bad checks but..?

she hasnt even gotten in trouble for them, they were all in a cluster about 4 years ago, maybe a little more i dont think more than 10-60 dollars more per check maybe one or two were a little more, she confided in me the other day because she feels bad about her past and wants to take care of this, but my question is how the hell did she not get a warrant or in trouble for this, could that happen?? i know once we went to walmart and she couldnt take something back because she was in her system for a bad check that she owed for like 25 dollars, i know that her bank paid alot of checks to like how they back up accounts like almost 900 dollars worth, she cant remember everyone she wrote checks to , so what can she do to find out and take care of them?? she got a letter 4 years ago from one of the merchants, it was maurices for like 140 dollars(her one only biggest one) and they said if she didnt pay they would prosectue so she paid and settled with them, what about the rest?? is it true that some merchants just dont prosecute?