The couple is claiming they weren't party crashers.
But this evidently isn't the first time they tried to get into an event where the President was without benefit of an invitation/vetting.

http://news.yahoo.com/s/ap/us_uninvited_guests

The Secret Service is around the President at all times. But the fact people who were apparently uninvited and didn't go through the correct background checks could shake hands with the President has to be an embarrassment to the Secret Service and White House staff. It shows that there is room for improvement in security-a lot.

"When the snows fall and the white winds blow, the lone wolf dies but the pack survives."
Winter is Coming

Now this is the Law of the Jungle—as old and as true as the sky; And the wolf that shall keep it may prosper, but the wolf that shall break it must die.
As the creeper that girdles the tree-trunk, the Law runneth forward and back; For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.