I try calorie count with My Fitness Pal and holy shit it’s a lot of effort. Eat out and you’re screwed (estimated at best). When you include sauces and oils etc it’s really hard to be accurate in the best of times, and it’s just a pain to keep on top of. Best option is to avoid any so you don’t have to count.
I imagine almost everyone will add bad data in a study at some point with the best of intentions.
I think being consistently inaccurate helps. If you always get the same thing at a certain restaurant, you can start by giving your best estimate of the calories in that meal. Then if your average weight doesn't move in the direction you want you can adjust your target calories to compensate.
I think tracking calories for a couple of weeks can be very enlightening for a lot of people, granted you don't have a personality type where this can get you into trouble. But for the long haul it's not really useful or even feasible, you're better off getting to know what sort of way of eating suits you best and how to correct if you're getting off course. Anyone can stick to a very strict regime for three months, but the trick is to stick to a proper diet you can enjoy for three decades and then three decades more.