One of the great great features of Lego Serious Play is that each person is the boss of their model--they build it, they say what it means, and no one can change that. When we work with grownups,being the boss of their build it helps the quiet persons have an anchor, and if anyone asks questions, it's about the model, not about the person.
We've invoked that rule when we do our come-and-go builds with kids, as a way of keeping the parents from being directive and taking the play out of play. But recently we used it in this situation: a little 3 year old girl was building away. The 4 year old boy next to her reached over and started fiddling with HER model, and she protested. The two moms involved said, "Oh, let him be." And when the little girl reached over to HIS model, they stopped her, saying, "Oh, that's HIS model." We invoked The Builder is the Boss of the Build Rule--not just out of respect for the persons involved, but as a way of undermining what looks like a sexist leaning.