Yeah, search warrants require probable cause to search a specific place. Air tags and the like are simply not accurate enough to pinpoint a specific unit in dense areas. I think the real answer here is to change how search warrants work: Allow a judge to approve a warrant for wherever the tag is--the police show up with equipment that can localize the tag. They do so in the least invasive manner they can, but the warrant gives them the power to go wherever the tag leads them.