Not really.
My sons and I had the opportunity to meet the President on October 30th. While standing and waiting for over two hours for the President to emerge I had the opportunity to closely observe the Secret Service agents. These guys were top notch. You could just tell that they were all like coiled springs waiting to pounce on you if you gave them any reason whatsoever. They never took their eyes off of the crowd.
Apparently, the Secret Service has a second string which is assigned to protect the remainder of the family.