If the majority of OC'ing "enthusiasts" were a tad more mature, there would be a lot less of an issue. There's a LOT of people in that group that don't really think before they act, or they purposefully try to get a reaction out of people.
If you're going to OC a long gun, be smart about it. Getting into someone's face, being boisterous, looking for an argument and, to a certain extent, dressing like a third-class citizen while doing it only hurts us and perpetuates the "redneck gun owner" image.
I am 100% for OC rights, and I'll OC a handgun in the summer if we ever get it passed. But OC'ing a long gun, especially when emotions are very high and we're VERY divided over this issue, is usually at most going to get a neutral reaction and will VERY rarely get a positive reaction, and that will usually be from a fellow gun owner who is already pro-OC. The majority of responses are going to be negative, and with every negative response comes a potential letter to a politician arguing for the other side.
IMHO, doing it quietly and outside of the public view is the best way to do it. Don't frighten the horses.