To complete my thought, we as HMBA members need to always try to educate other users on the basics rules. As discussed, there may be some people who feel that they always have the right-of-way, but there may be more who just don't know the rules.
We we are on two-way trails, we need to set a good example. When you ARE descending and you see someone coming up, stop well in advance and call out to them to climb through to let them know that the have the right-of-way. If HMBA members adopt this policy, it hopefully will spread to other users.