I made another accidental discovery the other day with the new 4th gen Apple TV. My TV remote control works to control player functions on the Apple TV.
Much has been said about how the Apple TV takes advantage of HDMI-CEC for basic control of connected televisions, ostensibly to allow control of volume, automatic input source selection (when the Apple TV is powered on) and power on/off of the TV using the Sleep button on the Apple TV remote. In addition to HDMI's ability to transfer sound and image information, HDMI-CEC also has other two-way data capabilities to allow basic control of supported displays/TVs. It seems to work both ways in more ways than I (and perhaps others) have first thought.
When watching a movie on the Apple TV the other night, I found that I could control some functions on the Apple TV using the buttons on my Samsung smart TV television remote - namely fast forward/rewind and play pause. These buttons are included to manage some of the Smart TV functions such as player controls for on-demand streaming and YouTube etc, but they seem to connect.
Now, I couldn't be 100% sure whether this is operating via IR or taking advantage of the HDMI-CEC standards, which my Samsung TV and the Apple TV both support. I don't suppose it matters really, but it's a handy thing to be aware of when watching your favourite show or movie and the TV remote is the closest thing to hand.