There's LOTS of tickets about zeny scamming, AND there's always the idea of people turning it on you and claiming you scammed them, without you actually doing anything, but most likely, if you deal with a large client base, all we'd really see is you trading people, most likely just... doing your business, but all WE'D see, would be tons of trades, of money coming in and out of your account. It'd be VERY hard for us to determine that, and if someone were to make a complaint, our most standard form of dealing with it, would be to temp ban your account to freeze transactions, and shift through the logs. Which, if you have a big client base, would take a VERY long time, on top of all the other tickets.
Bottom line is, I say hey, go for it, but if anything goes wrong, don't expect your accounts to be freed from investigation for a VERY long time