Having cleared the finish line, Blue is no longer racing and rule 24.1 begins to apply to her at this point. By changing course as she does, Blue interferes with Red who must change course to keep clear. Rule 24.1 requires Blue not to interfere with a boat still racing, if this is reasonably possible. If Blue had held her course for a few more seconds before heading off to pick up her lunch, she would not have interfered with Red. So, not interfering with Red was very easily possible for Blue. She therefore broke rule 24.1 and must be penalized.