Every jet that I’ve worked on with twin intakes had the two blanks connected and a warning flag.
Not blanks but on the C130 the nose wheel pin was connected by bungees to the pitot covers, so that in theory you couldn’t miss the pin as the latter had big ‘remove before flight’ flags. For some unknown reason (to me anyway) the ground crew would often remove the covers, roll up the bungees and lodge them above the pin, hidden in the nose bay. A thorough walkround would discover the pin but it wasn’t unheard of that an aircraft would get airborne and find the nosewheel wouldn’t retract…