One of the stories about a man who commited treason against the government was like that. He was actually put in charge of the task force to find the treasonist. He actually uncovered ANOTHER person doing it. But then he got caught - why? Because he hosted a dinner and one of his coworkers noted that his curtains were really, really, really expensive italian curtains. No way he could have afforded them on his salary.
And because of things like this, DH, then a government contractor, and all of his colleagues, and all other government employees (with the exception of the crooks in Congress) were sent questionnaires that they were REQUIRED to fill out. Basically:
What is your declared income?
If you are married, what is your spouse's declared income?
What do you own?
Where did you get it?
How much did you pay for it?
What is it worth now?
We were supposed to give the US government a complete inventory of everything
we owned, down to our pocket lint. We've been married for almost 40 years. There are only a few things in this house that we can definitively state what we paid for it and how much is it worth now. Rather than do that, DH retired a year earlier than our plans called for.