Jguss, I have no intention of being rude or harsh, but I don't find your statements to be accurate... :|
As far as domestic flights inside the U.S. there should be no issue carrying pipes or tobacco in a carry on. There simply isn't anything preventing you from doing so; so having to watch out for "a knowledgeable TSA agent who will use some flimsy pretext..." shouldn't even be worried about. It simply isn't going to happen over pipes and tobacco. Lighters, however, are actually subject to forfeiture rules but often slip by with no problems because the TSA sometimes doesn't know the rules.
It should be stated that you never actually deal with customs if you are flying domestically. You only deal with customs if you are flying internationally.
Regular TSA agents are the ones that don't know all the rules and regulations. Customs agents... Those people are a different breed and agency. In the event that they don't know something they look it up on the spot and you don't move. They are the watchdogs of their country; the very first line of defense against items and people coming off of an international flight. They check everything and they know their shit. They don't screw around when it comes to their jobs because it's a big deal. I'm not sure where you're traveling that your finding customs agents that don't know the rules? In my experience that would be like finding a unicorn. I've found that dealing with customs is the most stressful part of flying outside of the country even if you aren't bringing anything irregular with you. If you made it through customs and they didn't even bring up... Say, the amount of tobacco you had with you, it's because they knew it wasn't a significant amount. Not because they didn't know the rules.
As far as an "official allotment" goes, as I said, it differs depending on where you go. It isn't a safe idea to assume that it's a generous amount. You're right though, that's definitely something that has to be looked into if leaving the country.
I hope that helps.