A search warrant, like the name implies, is for a search of your property. Assuming the warrant is valid, the officers are not required to turn a blind eye to whatever illegal activity they find even if not specifically listed in the warrant. For example, if they had a search warrant to search for stolen property and find a meth lab, they don't just ignore it. Of course, people charged with crimes have good criminal lawyers to address these issues, unless the prospect of several years in prison is not important.
