True ryefly, some of DL's L1011's still do have the PCU's located on the seat, I stand corrected, however, IFE/PCU's is not necessarily a function of whether the plane is a widebody or a narrow body but rather a function of the seat design and the customer airline. (This I pretty much think you know anyways). None the less, if the call button is design correctly by the IFE manufacturer (i.e. recessed buttom insdie the control unit), your going to eliminate the problems of people accidenally dinging the button. Now I do agree that no matter what you do to the call button on an in-seat PCU, if the control unit is top mounted, you will get more accidental dinging then side mounted. Yet, when it is side mounted you will receive substantially less accidental elbow dinging. Majority of the accidental dinging is by people pushing every button to figure out what they do, or with kids fooling around. Yet the one thing you must understand is that on a wide body aircraft, especially a MD-11, 747, or 777, due to the size of the fuselage, if you placed the call button on the PSU rack, no one would be able to reach the button if they we're sitting in the center column of seats. I don't believe the answer is taking the call button out of the armrest, but I do believe that removing the PCU's from top mounted to side mounted solves a majority of your issues.
Yes, there are NO PTV's in E/C. True statement Early Air.