Biking against one-way traffic on the sidewalk—Stupid? Against bike laws? Both? Neither?

Wait… I just did that like 20 minutes ago! Are you talking about me?? Dude, I was looking for a restaurant, which is the only reason I was on the sidewalk going the wrong way, and I was totally going super slow, and yielding to pedestrians, and I was only doing it for like a block, and… huh? Oh, you're talking about someone else? I see. Then by all means, please weigh in on this weighty question in… QUESTIONLAND!!