Dnr doesn’t usually charge people with trespass, hunting or fishing without permission does not have the same requirements as trespass. You are completely correct about trespass, first offense is usually a trespass warning that could later on second offense be criminal trespass. But hunting without permission does not require anyone to be warned first the law states you must have permission from the land owner to hunt and if caught the landowner can prosecute or request DNR to.