If it is measuring differences in IR, then wouldn't the post it note work if it were placed on there before turning on the ECV? I am assuming that would be when it would take the baseline, because wouldn't things like if it is daytime or night time, etc. effect that? So if the sensor was completely covered when the baseline was being taken, then there would be no changes in IR, so presumably, the sensors would essentially no longer work, right?I would like to see a picture of the sensor. Maybe time for another trip to the park. But it depends really on what type of sensor is being used. I strongly suspect it is a basic (industrial) infrared proximity sensor. It could also be an ultrasonic "sonar" sensor but those aren't usually susceptable to getting dirty and needing to be cleaned as an earlier post mentioned being told about these scooters. It sounds like getting dirty caused the sensor to read a false positive, which means covering them will do the same thing.
This is a bit different that most auto flush sensors. Those (again, usually) measure changes in the sensor response. the sensor works by emitting an infrared light and also has an IR receiver that measures how much, if any, IR light gets reflected back. This is how most proximity sensors work. But because lots of things affect how much IR that reciever detects (changes in ambient light, temperature, just lots of things) the flush valves can't just set a threshold at which point it decides that a person is there or not, this would make them likely (as early models did) to go off all the time for no reason (something that still happens on failing units). What it does is take lots of readings and sets a baseline for unoccupied. You can see it flashing each time it gets a threshold reading and stops when you move away from it. So blocking the sensor here, in the first part tells it that someone is in front of it and it should not flush, much the same as putting it infront of an ECV sensor would tell it not to allow the scooter to drive. But on the toilet valve it goes further by, over time, ruining the baseline to the point that after a few minutes even taking off the postit note would not restore normal function, for a little while anyway.
I also question, what happens if I am on an ECV in a queue and end up behind one of these ECVs that won't move because it thinks the pole that holds the chain/etc. is a person. Obviously the pole will not move, but the ECV won't move until the pole does. Now I am stuck behind them with no way forward and possibly no way backward, especially if there is another one behind me.
Disney really hasn't thought this one through at all.