The CPL requirement that a deliberating jury be "continuously kept together" (CPL 310.10) has had its ups and downs over the last twenty years. People v Coons (75 NY2d 796 ) determined that the failure of the trial court to keep a deliberating jury together was a mode of proceeding error, a category of error which cannot be waived and requires no objection to present an error of law to the .
Then, in my case, People v Webb, the Court of Appeals said that Coons determined that jury sequestration did not require preservation, but that while it was a mode of proceedings error, this did not mean that it could not be affirmatively waived (78 NY2d 335 ). The defendant in Webb had expressly agreed to sending the jury home. The fact that mode of proceedings errors had been unwaiveable since 1858's Cancemi v People (18 NY 128) did not affect the outcome.
Then came People v Agramonte (87 NY2d 765 ), wherein the Court of Appeals said that Webb clarified Coons, and that preservation was required. Why? Because a mode of proceedings error cannot be waived! Ergo, this type of error must not be a mode of proceedings error, because Webb held that it could be waived. QED "Webb makes plain that the failure to sequester the deliberating jurors does not constitute a fundamental deviation from the proper mode of judicial proceedings." Ultimately, this was vitiated by Legislative changes allowing trial courts to send home deliberating jurors. But while the jury was actually deliberating, it has always been clear that they had to do so together.
The Court of Appeals has just decided People v Robert Kelly (#58 decided 3/24/11). In Kelly, one juror had to be separated from the rest due to child care issues, and no instruction was given to the remaining jurors to cease deliberations. It is improper for the jury to deliberate if they are not all together. However, the court held "there was no mode of proceedings error dispensing with the preservation requirement because the brief, momentary separation of the juror from deliberations was not the type of violation contemplated by the 'continuously kept together' language of CPL 310.10". If CPL 310.10 was worded differently (perhaps "continuously kept together, and this means no brief momentary separations of jurors, dammit") then it would be a type of non-kept-togetherness contemplated under the statute.
Therefore, if one or more jurors are separated from the rest during deliberations, you need to object to preserve the error for appeal.