So far, the Autobot and Decepticon insignias have appeared only on a few Transformers, in the form of hood ornaments (Mixmaster, Optimus Prime), the sides of cars (Barricade, Ratchet) and a steering wheel (Bumblebee in the first film). But that's all they've been seen. I miss them and would like them to be prominently seen on the bodies of Transformers, but I think that's not going to happen. Practically speaking, there's no way those insignias could appear on an object and nobody with a smart brain and sharp eyes could not know that was an alien robot in disguise, and then not run for cover or notify the authorities. Would Soundwave's Mercedes car mode would have worked if it carried a Decepticon insignia? Also, an insignia is no guarantee of being good or bad, as Jetfire and Sentinel Prime have proven. )From a storytelling perspective, using Autobot/Decepticon insignias can only work if: - the Decepticons are infiltrating Earth and not leading all-out assaults and invasions - there is little human involvement (only a few humans know of the war, government tries for privacy instead of telling everyone about the threat) The first factor is okay, a big film shows off big wars and I think most Decepticons don't really care for hiding for a long time on Earth. IMO the second factor is where these films slipped up.) It's a production matter, too: the insignias have only appeared on the sides of custom-built cars, trucks and construction vehicles, and generally do not appear on the sides of sportscars. Given how car-centred this franchise is, this has been problematic. Car companies generally do not want their products to be associated with good or especially bad characters. This goes back to when VW had issues with their Beetle vehicle being associated with Bumblebee; the same goes for the Ferrari (Dino) and the Pagani Huayra (Stinger). However, thankfully it's not like the insignias are phased out; I think that with the distinct vehicles seen in TF5 (tow truck, Volkswagen, etc) there should be some insignias printed on those vehicles, and hopefully for future films too.