Here is some information on Murguia at Wikipedia:
http://en.wikipedia.org/wiki/Janet_Murgu%C3%ADa
I think it is a poor strategy to confront personalities at public rallies, especially when all they represent is some leadership in some opposition organization.
This rally would be a good time and place to remind everyone that this immigration issue is not strictly a Mexican problem, but a problem from all different countries encompasing all different races, Europeans as well. And also it is a problem causing suffering in other countries besides the US and European countries as well. This would completely disarm the race baiting Reconquistas and leave them carrying water for people outside their organization -- people who are not latinos -- and people in other countries. The more you emphasize the universal nature of the problem, the more pointless the attendence of people from the NCLR will be, since they will be the only people who show up in support of illegal immigration. Everybody else will be getting a free ride from them. And any efforts on their parts to pick up the slack from anyone else is bound to carry them into the issue of terrorism from immigrant communities, something they will most certainly want to be avoiding.
A little news item to meditate on:
http://news.bbc.co.uk/2/hi/europe/8435857.stm
Yet another person from a Muslim country abuses some country's vital gun laws, this time it is personal not religious, but who can tell the difference any more?