Yea, mailing it is very unreliable ... When I lived in S. Korea weed was almost unknown. I couple of us use to have buddies from other countries mail us 'care packages' with d'erb in a shampoo bottle, cologne bottle etc - anything really that would disguise it. I admit that often it came through but many times it didn't. If it was found, the reciever never got nailed for it cuz you can just deny knowledge, and I NEVER knew a reciever to incur legal wrath for a spotted package. When I left Korea, I sent 2 such 'care packages' to my buddies and neither one of them made it through. I took precautions on my end - shady address, used gloves etc. so I never got sussed out, and neither of my buddies did when the package was meddled with either. In fact one time while I was still over there we got the package but it had been rummaged through and the 'goodies' removed b4 they sent it on --- go figure!
Anyways, point being - mail is fairly safe as far as risk factor if precautions are taken, but really really really unreliable.
Your best bet: homing pigeon!