Stop telling them this in advance! They can’t get at your work material or deliberations. Just give them a general affirmative and go on to nullify that shit.
Also, at the point you can’t seat a jury because they’re telling you they won’t convict there has to be some kind of slaughter rule. To stop wasting the court’s time if nothing else. Because at some point you’re just letting the prosecutor choose a verdict, not a jury.