I won 0.175 BTC once in a poker tournament, more than 2 years ago, and I think there's no one left among the people I know, who didn't hear this story from me at least once. 
But hardly it was an amount sufficient to put one in danger if he/she talked about winning it (around $400 at the time of winning). Of course I agree with the OP on that if someone can't stop bragging about winning really big, you are putting your life and the lives of your close ones in danger. Winning big money should be enough to satisfy your ego. Don't be greedy for another satisfaction in the form of admiration by the people you know.
But hardly it was an amount sufficient to put one in danger if he/she talked about winning it (around $400 at the time of winning). Of course I agree with the OP on that if someone can't stop bragging about winning really big, you are putting your life and the lives of your close ones in danger. Winning big money should be enough to satisfy your ego. Don't be greedy for another satisfaction in the form of admiration by the people you know.