I bot on a wrath account, level 80 herb/mining, I prefer to run BC/Wrath profiles as there is far less traffic. In many cases the prices are just as high - if not higher (adamantite 150g/stack elementium 80g/stack for example). I have always transferred gold in small portions (being 5-15k) either logged into both accounts in trade windows or giving the gold to a guildmate who gives it to me.
I also have a bank toon on my cata account, I invite my bot, dump gold, gquit and rejoin a friend's guild with perks. I have transferred over a million gold between all my toons this expansion, if my account were looked into the activity wouldn't seem abnormal however.
If I were to sell gold - which I haven't in recent history, I would use an alt account (probably a bc or wrath account - not vanilla) and do it through Gbank. It's easy to buy a month in trade chat for 15k and dump a large amount of gold one month through that alt gbank account with little suspicion.
In the end, it comes down to execution and luck. I started botting at the beginning of BC. I have been banned one time, that was after coming back to wow after a break on a mid level rogue and grinding/skinning for like 4 days straight in nagrand whilst listing shitloads of skin on the AH. I would never have done that under normal circumstances but tbh I didn't really care. Pirox recorded over 35million honor farmed in sept 2010 - end of wrath, most of which was spent on epic gems and sold for gold. Bans are very easy to avoid unless you are careless or very, very unlucky. Practicing semi-safe/commonsensical techniques will 9/10 times keep you from being banned, regardless of what methods you choose.