Old botting mantra: Don't bot on an account that you are afraid to lose.
There is no 100% undetectable bot. I think the "Buddy" crew are close, given their longevity and success with Gatherbuddy/Honorbuddy in WoW, but people still can get suspended or banned. People do stupid things, like put up hundreds of auctions, bot for significant time away from a computer (and possibly get stuck on things), vendor extremely large amounts of things, or run public profiles (nothing quite like seeing a kill train of bots go through a path!) -- none of which is the fault of the software, but of the end user.
We don't have all of the information for why this player was suspended, but neither does he. He has a ticket from Trion, and those of you that have botted WoW before know that Blizzard does a similar thing with occasionally generic or uninformative emails. Player reports are the most common at this stage of the game in Rift, it seems -- all it takes is one person wandering by and seeing someone following a set path over and over, then filing a ticket. GM invisibly shows up and watches, and poof, suspension.
Anywho, back around to point, don't bot an account that you're afraid to lose.