Hey,
First of all, there is always, and will always be a risk. Number one rule of botting is : Don't do it if you don't want to get banned.
It will happen eventually, so if this is a account you care for, don't bot on it.
Get yourself another account you don't care about and bot there.
On another note, if you are BG botting you will get banned for sure given the right amount of time, maybe not in 1 week, but you will get yourself banned, bg botting is one of the things i personally would never do myself, in the smallest bg's there are 9 other players on your team and 10 on the other team, if your bot decides to do something obviously botlike, you have earned yourself some reports. I guess everybody who has done some BG's on it's own has seen some bottingtrains, or other really obvious stuff only bots would do.
So afk bg botting? I'd say yeah you are in for a big risk, botting bg's with user controlled movement? not that big, but still instant interrupts, instantly buffing/decursing/purging can be quite obvious too.
I'm not saying everybody who instantly pops trinket, purges a BoP or Reflects a fear is a bot, but if I see someone instantly trinketing my Kidneyshot to not die but then chilling in my smokebomb until he dies, or a rogue cloaking my instant freezingtrap but afterwards doesn't walk out of line of sight from a sheep? Im gonna assume that's a bot. Either you have understanding or you don't have it.