Warrants are pre-trial activities to collect evidence, defendants (or, more likely, their attorneys) are still able to challenge the admissibility of evidence s

Warrants are pre-trial activities to collect evidence, defendants (or, more likely, their attorneys) are still able to challenge the admissibility of evidence should a case go to trial. If it turns out a search warrant was requested in bad faith, or the trial judge (which won't necessarily be the same one that signed the warrant, and then there's appeals courts) finds the warrant was defective (overly broad, lack of probable cause, etc.) and should not have been issued in the first place then any evidence stemming from it could be thrown out. "Fruit of the poisonous tree" simply means the entire chain, the initial evidence that was improperly acquired and anything that was discovered based upon it, gets thrown out. If a warrant was issued to dump the full contents of your phone, and they used location metadata from your photo library to start determining other locations to search and got warrants for those, then that entire chain of evidence gets thrown out if the court finds the initial warrant for your phone was invalid.