Should I be concerned about recorded jail calls in a North Carolina federal criminal case?

A WORD OF CAUTION:  Please do not speak to anyone about your case other than your attorney(s).  If you speak to another person about your case, that person may testify against you. Also, please do not speak to anyone on the phone about your case.  The calls are being recorded.  We see recordings of jail calls regularly in discovery.  The use of codes to communicate is ineffective, and the codes are easily decipherable.