The screen is hardware. It's wired to the camera. Both are independently addressable via software. Making a small screen consisting of only a single LED and moving it close to the camera doesn't change that...so long as the two are hardwired and one or both are programmable, there's no certainty.
Short of removing the camera from the device, physical disconnection is the next best thing. To put it another way, a camera can shoot at 1/2000 of a second. That's quick enough that a person will miss the blink of an LED even if it's activated 10 times as long as the shutter is open. So any indicator is going to have to programmed to show future and/or past events to conform to the human time frame...or as some might say is the case with all things photographic, it has to be programmed to tell a lie to be useful. It's just a matter of whose lies it tells.
