It depends if a gm is checking the co-op chanel or not , if he is and you are using the farmer he can kick you out of the game or even ban you.
I would recomend using it at night time when no gm is checking on a chanel
you could use it early in the morning too?? right..
I know of GM's in New York state and Germany, so it can be difficult. There is the picture server that takes random pic and you can get banned for that. I farm around Midday time and have been ok so far. Always a chance of a ban with adding euros, and using a private VPN helps.