In contentious situations, I tend to be very frank and open with clients about my dealings with other professionals, both on our side where I am the design team or inspection team leader, as well as on the other side, where I prefer communication to be open and transparent at all levels.
In this regard, I prefer e-mail communications, as opposed to huddles in hallways, but that is part of what I do - I set things up so that clients legal representatives can "do the deal" that needs to be done, my work adding pressure to perform on the other side.
Deal-makers, whether legal or property (estate agents) generally preserve their cordiality towards each other to allow the best chance of a favourable reception for their clients proposed deals or settlements - it confers no benefit on anyone if an entrenched attitude leads to three days in court at considerable expense when a morning would do.
The trouble is that clients can be emotionally involved in the proceedings and may be looking for revenge, a penalty against the other party, or the stiffest sentence and this is precisely the wrong way to present with a judge or the other side, who can form the opinion that you are unreasonable and possible a less than frank witness.
So therefore, clients should let the professionals do their work, but where solicitors are concerned its no harm to keep on their case to get people to the table - otherwise just let them sort themselves out in terms of their professional relations with the other side.