The person in front when he purchased his seat entered into a contract to buy his reclining seat, if you restrict his right to do so even if you do not exercise yours you will almost certainly find yourself being asked to remove such devices by the flight staff. Purchase the extra legroom seats at front or escape door row. Making someone else remain uncomfortable for your own comfort is very difficult to justify, you may be tall, they may be infirm, arthritic etc and uncomfortable upright.

I could only imagine using such a device as a last resort for THAT GUY that slams his seat back repeatedly.

Delta Economy Comfort is well worth the $ IMO.

Probably get YOU thrown off the plane.

and it should. he bought a reclining seat, as did the person behind him. it isn't his fault if a tall/long legged person is the one behind him.

Asshattery for sure, just to answer the OP!

Put it this way, how would you like for someone to use that device on YOUR seat, especially on a 16 hour flight such as over the pond to Africa?

If my seat does not recline I will push the button for the cabin staff to investigate.
If you do not like my seat reclined while I sleep you should try reclining yours. If you do not like reclining sit in the front row.