Does a no knock law goes for a harrassment cases?

Knock and announce is constitutionally required in the absence of some exigency.  Failure to knock and announce may in some circumstances, lead to the exclusion of evidence obtained. No knock entries, require reasonable suspicion that knocking and announcing police presence would be dangerous, futile, or would inhibit the investigation such as destroying evidence.  Knock and announce also does not apply to vacant or abandoned buildings.  No knock does not necessarily apply to any particular type of cases, but only reasonable suspicion that announcing the police presence could be dangerous, futile or inhibiting.