No driver, groom or caretaker, once admitted to the paddock or receiving barn, shall leave the same other than to warm up said horse until such race, or races, for which he was admitted is contested; provided however, that in the event of an emergency, trainers or grooms may leave the paddock but only with the permission of the paddock judge in which case the paddock judge shall maintain a written record thereof. Such record shall be delivered to the presiding judge. A trainer may leave the paddock before his horse completes its engagement, but may not return to the paddock unless approval by the presiding judge has been given.
N.J. Admin. Code § 13:71-6.14
See: 20 New Jersey Register 1175(a), 20 New Jersey Register 2071(b).
Added text "A trainer may ..."