"Unreasonable" in my mind is the grounds for the search found in the warrant and nothing more.
Suppose a cop has a warrant indicating someone is suspected of possessing a stolen piano. The cop breaks into the person's dwelling with a sledge hammer and proceeds to smash everything in sight. Within the smashed remains of the person's desk, the officer finds a quantity of drugs.
Should the drugs be admissable as evidence? Why or why not?