No, the TSA's primary directive is national security, followed by passenger saftey, then smuggling, be it people, animals, or drugs. But even then they care more about someone trying to smuggle coke or heroin in meaningful quantities than your dub. Still doesnt mean they don't care.
If you try hard to hide something, the TSA will notice because it could be a bomb/knife/gun. They probably don't really care if you have some weed, but they if they see you hiding something they will try to find it, and if it turns out to be weed its hard for them to turn the other way. Ive found the best way is to just put it in a bag in your suitcase. Nothing else, not blatant but also not hidden. All but once ive been fine, and the time I wasn't they simply left a note saying they removed contraband. If they would have found it through the scanners, they probably would have had to make a bigger scene.
Lastly, UPS and Fedex DO search for weed, and when you ship with them you agree to declare everything your shipping. If they have reason to believe you are shipping something illegal, they can and will open that package, and report it to local law enforcement. They might not be actively searching, but sometimes the DEA will have a drug dog go through warehouses and try to get as many as they can. If its just a little it will get tossed, if its a lot they will try to deliver it so they can see who picks it up.
The best option is actually USPS. Its both the cheapest and ironically, due to a shitty budget, the worst at security. Still not a guarantee you will get it there, but they simply can't afford to check every package for drugs. Also if you send it overnight it won't sit in a warehouse or sorting facility for very long, and that is how you get busted.
TL;DR. Use USPS, don't try to sneak it on, if brownies just put em in your suitcase in some Tupperware.
Source: I have a "friend" who used to ship weed as his full time job.
