I think a tiny amount of paranoia can be good, as it has stopped me from telling people although I did tell a close family member and a friend of mine, and I was still a little paranoid after that, and would recommend not telling noone in future and I learnt a lesson after that, just don't tell anyone, no matter how much you trust them as it can cause an unhealthy obsessive amount of paranoia, however it keeps me on my toes now.
However paranoia rules the drugs undergroud and one of the major cause of problems. I don't want to get you para or anything but someone did get raided after posting vids of his grow room on youtube. I would highly recommend to get the video of somehow, better to be safe than sorry.
I just think your young and nieve(spelling) but haven't we all.
I had also a similar situation as yourself, and it's all a learning curve and from now on, you will be a lot more cautios and you have to listen to people older than yourself, as they are usually a lot more wiser and have more life experiences with a wide range of situtations, I used to think what the fuck does that dude know. Then you start to realise that old man was talking sense and knows what he's doing and if you can learn from people, then you can technically rule out several problems with there help.
Peace, good luck and learn from this, don't take offence to it.
Peace
mj123
P.S You asked if they would take someones word across country, and the answer is yes if they have sufficient evidence to send you down, as they would contact your local authorities and let them know your name and address and they would also pass on the evidence as well, so make sure you have everything out your house and make sure to keep a small amount in your house at one time, and find a remote locations and bury your ganja and make sure it's well wrapped and it a safe container. If they do have evidence from this guy, they wont bust you straight away, the law enforcements will have to start gather intelligence on yourself.