Have you ever punished for something that happened in the past that you just hadn't known about at the time?

Last Labor Day (08) I was dishonest about where I was spending the weekend, and my parents just now found out where I really went and are furious. Something that happened more recently is what revealed the events of that Labor Day weekend, so I can understand why they are upset, but it feels unfair to be punished for something from the distant past, and that's what they've done because I basically was given two "sentences." I've grown and accomplished a lot since last year, and in between the two things didn't get into much trouble at all. I feel like only recent events should be focused on. This wasn't a case of me running off to Vegas or to shack up with my boyfriend, and I won't go into details about it all here because that's not really the point of the question. I am just wondering what people think of the fairness of punishing for something that happened nearly a year ago, and if anyone had similar experiences.