I agree with Tony. Went around and around on this with Philmont during 2 treks (3 crews each) in 2006 and 2011. Both times we used Freezer Bag Cooking method. In 2006 Philmont allowed it as a "demo". By 2011 they allowed it officially in their handbook but activly discoraged it when we got there. We won both times and did not carry the large pots.
All of Tony's points are valid. Philmont is simply out of touch on this as they are with most gear matters.
Our trek this year will use individual, microwave safe tupperwear bowls rather than freezer bags so the issue of "chemical leakage" is completely bogus. The safety issue Tony addressed well. Those giant pots are a much bigger hazard than small stove/pot or Jetboil setups.
Finally, Philmont needs to "Go Green" by embracing modern backpacking cooking techniques. Those giant pots waste tons of water and fuel, the soaps needed for cleaning are awful for the environment and the sump drains at every camp need for the Philmont Way are bear hazards and disgusting, too.
As for the "freezer bag method increases trash" complaint, the tupperware method elimiates that objection. And I saw a lot of disgusting disdhrags and scrubbies in and around the sump drain sites.