Hi there, I have the same problem with my macbook pro 8.1. When the laptop it's off and I connect the MagSafe it switch on automatically.
There is also another problem related. The battery is not charging. So to have the laptop ON I need always the MS connected, and the MS led light its permanently green, and the message next to the battery sign is "Not charging". When I disconnect the MS, the laptop turns off instantly.
To fix this second problem I tried to: that I found here in this successful video I found in Youtube.
That are the instructions of the video to be followed in this specific order:
"Power down > Take off the battery > Take off the MS > Hold on for 5 seconds. Then when you put it back together you first: Put the MS connector on > Wait a few seconds till it goes Green > Put the battery in > Wait a few seconds > Turn it on: Fixed my problem."
Everything ok, but in the penultimate step "Connect the MS > Wait 5 sec > Turn on" I cannot do it because the laptop turns automatically on after the MS connection step. So its not possible to do it because it switch on before the 5 sec. necessary to wait for before to Turn it on.
I tried with another good MagSafe but it happens the same. And there is this video with lots of comments of people that had success doing that, so I think it must be related with the programmed obsolescence. Then the parts are working good, and must be a strategic solution to fix it. The solution of the video its good, but for that I need to fix the "Auto power on, when connect my MagSafe" problem.
So which can be the way to find a solution for this?