Opposing Expert’s Allegedly Inaccurate Description of Use of A.I. Did Not Justify Modification of Scheduling Order on Facts Presented

“This is a Federal Tort Claims Act case involving allegations of an unlawful shooting by a Bureau of Land Management ranger.”  Martin v. U.S.A., 2026 WL 2582963 (D. Nev. Sep. 1, 2026).

Defendant moved to reopen and extend case management deadlines based on Plaintiffs’ expert’s having used AI, allegedly more extensively than disclosed. The motion was denied based on lack of diligence.

The chronology follows:

• February 10, 2025: The parties held a Rule 26(f) conference. The court wrote that there was “no impediment to proceeding with discovery.”
• March 26, 2026: Plaintiffs disclosed Tom Melton as an expert and served his report.
• May 1, 2026: The extended rebuttal expert deadline expired.
• June 9, 2026: “Melton testified at his deposition that he used an artificial intelligence aid to assist him with grammar and sentence structure in his written report…. Defense counsel knew as of at least that date (June 9, 2026) that there may be an issue with the use of artificial intelligence. Indeed, counsel began researching the issue and looking for an expert at that time.”
• July 16, 2026: “Apparently due to some sort of scheduling issue, Melton’s deposition was continued and eventually completed….”
• August 10, 2026: The discovery cutoff expired.  “On the discovery cutoff, Defendant filed the instant motion seeking to reopen the rebuttal expert disclosure deadline and to extend the discovery cutoff (and subsequent case management deadlines) by 90 days.”

The basis of the defense request was:

Defendant explains that, based on the record in a different case involving Melton, counsel “believes that there is a possibility” that Melton has misrepresented the extent of his use of artificial intelligence.

Defense counsel had “suspicions” of misrepresentation.

For the unexpired discovery cutoff, the court explained that good cause is required to modify an unexpired case management deadline.  Good cause “turns on whether the subject deadlines cannot reasonably be met through the exercise of diligence throughout the allotted period…. The diligence obligation is ongoing and the movant must have been diligent throughout the entire period already provided….  Courts may find a lack of good cause when, inter alia, the movant did not promptly seek judicial relief from the subject deadline.”  The burden of proof is on the movant and if it is not carried, “the inquiry should end.”

For the expired rebuttal expert deadline: “Seeking to revive already expired deadlines requires an additional showing of excusable neglect….  When there is no threshold showing of diligence for good cause, however, such request is properly denied without the need to separately address excusable neglect.”

Here, the inquiry ended:

In this case with an already-extended discovery period, the record reflects that defense counsel was on notice of Melton’s testimony on his use of artificial intelligence since at least June 9, 2026. Although counsel represents that he began immediately researching the issue and trying to locate an expert, he did not file the instant motion until the last day of the discovery period more than two months later. The Court agrees with Plaintiffs…, that the failure to seek relief for two months shows that Defendant was not diligent….

The court rejected the defense argument that the deposition was not concluded until July 16, 2026: “Defendant cites no legal authority and provides no meaningfully developed argument that a party can sit on its hands in seeking relief from an approaching case management deadline simply because a portion of a deposition is rescheduled. Again, counsel represents that he had spent the preceding weeks looking into the issue and trying to find an expert, so any need to seek relief from the case management schedule was known weeks before the second part of the deposition. Defendant fails to explain why counsel could not have conferred and sought relief from case management deadlines during the intervening period.”

The court added: “Defendant also cites no legal authority that a party must already find and retain a particular person to act as its expert before it can seek relief from the expert disclosure deadlines.”

In a footnote, the court wrote: “The lack of diligence is dispositive of this motion. The Court notes that there is also some force to Plaintiff’s additional argument that speculation as to the use of artificial intelligence seems a weak basis for an eleventh-hour request to extend case management deadlines yet again.”