This is for park visitors of the future who found this thread in a search: These pins do indeed still work, but the only places I noticed that were still working were:
El Río Del Tiempo / Grand Fiesta Tour @ EPCOT towards the end, in the large fireworks room
(1/22 confirmation and video added)
It’s A Small World @ MK in the giant blue unity room, final room where all the nationalities are together before saying “goodbye” to guests.
(2/22 confirmation and video added.)
Pirates of the Carribean @ MK, right before the drop off and inappropriately throughout the cannon scene. (It’s a very dark ride, and you’re sharing a boat with others. Had to cover it up, to avoid distracting from the moment)
(1/19 confirmation) (2/22 did not activate. Transmitter may have been damaged or removed)
Haunted Mansion @ MK - At the very end, all LEDs blink in unison, simulating a heart beat.
(1/19 added) (2/22 did not activate. Transmitter may have been damaged or removed)
Dinosaur @ AK after you return back to the present.
(1/19 added) (2/22 did not activate. Transmitter may have been damaged or removed)
Not bad for a forgotten
21yo feature.
Rides previously known to go off, but did not ride:
Tower of Terror @ MGM/DHS
Maelstrom @ EPCOT was also known to set it off, but it was closed still, and probably won't ever work with the new Frozen Ride. Dream Builders of 2016 will probably find the infrared transmitters, be all confused about what on earth that is for, and get rid of it.
(1/17 and 1/19 Update - No longer works with ride)
Spectromagic parade @ MK has been disassembled and turned into collectable LE pins, so it did not go of, since they reintroduced the Main Street Electrical Parade.
Did not notice it during:
Space Mountain @ MK
(1/19 Update - finally rode it. I was jerked around so much that it was lighting up throughout the ride, but whenever I checked, it lit up in the same fashion as if you had pressed the button yourself, so I could not confirm)
Peter Pan's Flight @ MK - (supposedly only lights up the white bulb, so even though I was holding my bag, I might've not noticed whether it did anything or not)
(1/17 Update - Batteries were too low to determine) (1/19 Update - Ride was closed for refurbishment)
Pretty sure there were more. I will edit this list as I find them