It is very important that people know their rights and responsibilities under the law. While a mediator can provide information to participants in mediation a mediator cannot give legal advice. In Divorce Mediation I always advise the participants that at some point they will need an attorney's view. I have a list of Advisory Attorneys who have told me they will give mediation participants advice without requiring a large retainer. One reason people choose mediation is cost effectiveness.
Some attorneys like to attend the mediations. I do not prohibit attorneys from attending mediation sessions, but I am uncomfortable thinking the participants are paying for my time and the attorney's time as well. Sometimes I think attorneys are uncomfortable charging a fee while attending a mediation session unless they get very involved in the mediation. That can be counter productive since mediation is most effective when the clients speak and identify what their goals in mediation are.
In Divorce Mediation there can be emotional issues to work through that attorneys are uncomfortable with or that attorneys think are unnecessary. In those circumstances, attorney participation is less helpful.
Bear in mind, most attorneys think it is their job to advocate for their client. Advocacy is important in litigation, but less important in mediation. A skillful mediator assures that each participant has the opportunity to state their needs and in that circumstance "advocacy" is less important. A mediator is not deciding the outcome, the participants will determine the outcome, so advocating a "position" to the mediator has no traction; the mediator does decide anything.