I'll concede the laws in different states are different but the 4th Amendment is a Federal concept. Generally the only way a search this broad can occur without warrants is 1) consent, 2) exigent circumstances, or 3) Probation or Parole search clauses. Although the vehicles might be searched pursuant to "probable cause," as described, this action would have required a search warrant or court order for the IP address and either warrants or one of the aforementioned 3 for each of the houses they searched. Either there's more to this story or the Michigan DNR has a lot of time and resources on their hands....or both.