concern: >> it really is the tip of the iceberg. this and things like ribbon cuttings that went on for five days of hawaii vacations, misuse of gsa credit cards. we're seeing a pattern at the gsa and, remember, the gsa sets the standard for, if you will, getting a good value for the american people for all of government. >> reporter: now, the $823,000 las vegas conference was the initial event that drew so much attention. investigators say that conference included a fake awards program so participants could eat for free on the taxpayers. some leading democrats believe this week's four hearings here on capitol hill should also include gsa officials who served under president bush to see how far back this behavior goes. a key house republican on this matter offered this assessment based on what he's learned. >> from the whistleblowers that we've had come forward, they've told us that this is something that's happened over the last couple years, it continues to escalate.