Early in a lifecycle of a project, it should be possible to identify characteristics of the project that can warn the project manager for threats heading in the direction of the project. This is called a "red flag". When a red flag is identified there are a good reason to spend extra time with the risk analysis and go over the estimates one more time. You know this red flags can be real show stopper, and the best use of time in such situation is to try mitigate or avoid the risks. Dealing with them when they arrive, will be unnecessary expensive and far from pleasant.
Red flags is different for each client, but there are some common characteristics;
A part of the EasyRisk methodology is to look for this red flag and act on them.