I just spotted a glaring example in The Outer Limits: Falling Star
Right after Melissa's interview with the DJ, the camera does a far shot pan from the studio to another room. As this happens, it passes a computer monitor in tge foreground that is not only an obvious light box with a printed overlay of computer graphics, but the bulb inside is shining light all over the wall behind it!
And why the use of a fake monitor to begin with? Couldn't the production studio just have used a real computer system from one of their own offices?
Apple and Microsoft didn't want to pay for product placement ;)