An example of this would be a case involving domestic violence. Several professionals believe that mediation is inappropriate here as it may just provide another ground for the abuser to harm the victim once again. Likewise, a physically abused person is almost always unable or would have a huge difficulty in expressing and protecting their own interests, especially in front of the perpetrator himself/herself.
One of the main features of mediation is that it's more cost-effective than filing a legal action and taking that case to court before a judge or jury. In cases where the mediators can enhance the problem-solving skills of all sides and assist them to steer clear of further disagreements or clash of opinions, then that mediator is quite beneficial.
In divorce actions, mediation may be mandatory depending on the rules of the local court. This is oftentimes required for child custody and visitation disputes, so that both parents could converse with a court-appointed mediator and see if they can resolve their problems even before putting their case before a judge.
In cases where the mediators are able to improve the problem-solving skills of both sides and help them steer clear of further quarrels or clash of opinions, then that mediator is pretty effective.