It seems like a good time to review the kinds of activity that most frequently draw the scrutiny of fraud departments of mileage programs. While not an exhaustive list, these are some of the biggest factors:
# premium class international award redemptions for other people, especially several in a short period of time.
# heavy mileage earning from a single partner or source
# one or more of the above across multiple accounts accessed from the same computer or IP address
# sponsoring upgrades for multiple different individuals
# selling awards