I have been auto-buying for years without being frozen, but only after having learned a few lessons the cold way. You'll be totally fine with a sensibly calibrated auto-buyer and a lot of patience. Just keep repeating this phrase to yourself: don't get greedy. Don't tune the auto-buyer to run too quickly and don't run the auto-buyer too often. Scoring valuable items is highly addictive, and you can easily lose your restraint with a lot of success, so again: don't get greedy.