While I have not used Augur personally, the following warning is not unique for Augur. It is a starting industry and coding is a human endeavour. Errors are bound to be made. As long as people using these services are aware of the potential issues, this is all part of stage blockchain is in still.
”An analysis of irregularities discovered in the Augur decentralized prediction market platform has identified a number of design flaws. Namely, it identified a potential attack vector based on discrepancies between a market’s expiry date and its outcome date.” - Augur Prediction Market Platform May Have Design Flaws
Still, commons sense and caution go a long way, so indeed, buyer beware. As with all innovations, it is the balance of risk/reward.