Angelina had a killer dress and no date. She figured she'd show up, avoid George and Audrey, and escape when she got the chance to pour herself a drink and study Quidditch plays.
She didn't want to be alone in the same room with him. If only she had found a date to dote on and ignore George. She figured making out with a guy in a club didn't justify inviting him to a wedding. It sent the wrong signal. She got a glass of champagne and a cupcake and went to hide in a corner.