As far as the retailers (and customers in general), I'm betting a lot of them fall under the umbrella of unawareness; a little education is likely more than enough to put a stop to it as far as online retail. I'll wager that Amazon allows these products because they believe it to be an actual plant product and nothing more.
The bigger challenge will be putting an end to the poaching, since demand is not likely to go away anytime soon.
Agreed, but cutting off international supply, or at least making it harder might help lower demand a little.