I agree that that risk exists as well, but much of SIAI's efforts revolve around increasing discussion of the risks of AGI, not just holding back their own efforts. Slowing down other efforts through awareness of the dangers is a factor that should be considered.

Also, discussions of caution may increase the number of "desirable organizations" working to develop AI. In terms of your model, such discussion could turn a black-hat organization into a smiley-faced one. No one is going to release an AI that they actually think is going to wipe out humanity. What's more, not every well-intentioned organization would be one we want to build AGI. While certain organizations are more likely to be scrupulous in their development, the risk of well-intentioned error is probably the largest one.

In addition, one should consider the extent to which Friendliness can be developed in parallel with AGI, not just something added on at the end of the process. If we assume that no one is currently close to AGI (a fair belief, I think), then now is a fantastic time to help support the development of that theory. If FAI can be developed before anyone can implement AGI, then humanity is in good shape. If it's easy to add FAI to a project, or if knowing about workable FAI would not help a group with the problem of AGI, then the solution can be released widely for anyone to incorporate into their project. SIAI's goal is not to be the ones to implement the first superintelligence, but just to make sure that the first one is Friendly.