Multiple issues of the Daily Planet, in this and other episodes, have the same story in the right column of the front page: "Survey on Pollution Advocated."
Even though "Crime Wave" was set in and aired in 1953 most of the vehicles used appear to be from the forties.
Mr. Big and his gang are watching amateur footage of some of the Daily Planet workers. Clark Kent is shown running into an alley, and a few seconds later Superman appears and takes off flying. They watch that scene a second time, AND THEY DON'T GET IT.
When The Number One Man and his henchmen are watching the footage and first see Clark run into the alley, then Superman come out it's absolutely ludicrous that they didn't put it together. However, there is clear indication that Sally figured it out, but as to why she didn't clue them in is unknown.