This thread is an example of how confusing the whole legality issue is!
I'm not a user so it doesn't really concern me, but if I was I'd be alternately delighted and disappointed by the changes in the Cannabis laws.
I would certainly be too scared to try and negotiate the purchase of it, in no small way because, as we know, in Thailand, if the police say you're guilty of something, at the very best it just gets expensive.
I actually think it should be treated like alcohol - licensed and regulated, but then I think the same in the UK - at least the laws are clearly defined here.