According to the Pay Attention Book No Observers are allowed.
How ever please note what a paragraph from the following letter says.
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To all Circuit and District Overseers May 6 2002 Page 3 Para 2.
Assisting Elders with Judicial Matters.While it is best for a travelling overseer not to serve on Judicial Committees, he can assist by being an advisor when needed. In that event, during the hearing of a case where a travelling overseer sits in as an observer, he can note how the judicial committee conducts the proceedings, having in mind what is stated on pages 110-6 of the Pay attention (ks91) book. Thereafter, when the judicial committee meets for consultation among themselves, a travelling overseer may be asked for assistance on some particular point or points. It is important for him to listen carefully and to make sure that he has some reference in print to support any advice or counsel that he may offer. Furthermore, he should not be influenced by personal feelings or opinions on the outcome of the case. For matters pertaining to scriptual freedom to remarry or nonneutral employment, it is best for these questions to be sent to the branch office in writing, unless the matter is clear-cut. If a congregation does not have enough qualified elders to serve on a committee, the circuit overseer can recommend elders from a nearby congregation.
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