Is it difficult to exclude live witness testimony on exclusionary rule grounds?

The accurate characterization of the difficulty in excluding live witness testimony on exclusionary rule grounds is indeed that it is generally quite challenging. The exclusionary rule primarily aims to prevent the use of illegally obtained evidence, particularly derivatives of unlawful searches and seizures. However, live witness testimony is usually not considered "evidence" obtained through such means; rather, it is the result of a personal account of what the witness has observed or experienced.

Therefore, when it comes to live witnesses, issues surrounding their testimony often relate more to credibility, relevance, and other evidentiary rules rather than constitutional protections under the Fourth Amendment that the exclusionary rule embraces. Because of this distinction, courts typically do not exclude live witness testimony even if it pertains to events connected to an illegal search.

Overall, the context in which the exclusionary rule applies—primarily focusing on physical evidence or statements derived from illegal actions—explains why excluding live witness testimony is indeed difficult.