Hi Elise,
Glad that sad little story of the stubborn guy had a pretty happy ending for you, especially with the successful use of jam camp "rules". They are actually more like protocols that have slowly developed naturally in bluegrass, according to common sense and courtesy. I didn't "make" any of the protocols. I just interpreted and sort of codified them from a great deal of observation in many places and times. The closest thing I have to rules in jams concern tuning, timing, and being on the right chord. Those "rules" are bound to be broken sometimes, and the next rule is, let's keep trying to get it right but not be too uptight about minor mishaps. It's a jam, after all, and the payoff is in fun and harmony.
After that, different jams can have different ways of reaching the goal (musical fun), and people will gravitate to their own styles of doing it. The guy you mention is comfortable with what he is used to, and seems to have made the mistake of considering his way "the right way". I am very careful with the use of terms "right" and "wrong" when it comes to music. As in other parts of life, there are many ways of doing things that work for different people, and trouble can arise when two or more people stubbornly maintain differences on what is "right", implying some objective standard. This is the same kind of thinking that over history has led to some pretty bloody wars! Humans have to learn better ways if we are to survive together.
The three jamming "musts" I've laid out (tuning, timing, agreement on chords) have a tremendous degree of consensus. Beyond those, when in Rome I just might go along with the Romans. For example, old time jams do have some protocols different from bluegrass jams. (There are no "solos", for instance.) The typical protocols listed on my Jamming Pointers sheet are more to be thought of as a sensible and trustworthy guide for bluegrass jams, but there are many ways to have musical fun.
Pick on, have fun, and stay in touch!
Pete