Hi, I realized as many from here, that when the MBP is connected to the plug, you can feel just a rare sensation on the unibody case of the computer. So I made a test, and I just "kissed" the computer to see if there is electricity (the test you use for batteries, with lips or tongue) when connected, and OMG! This little gives you a good bitting shock! Not pretty loud, but anyway... So it's not on all the case, but near the magsafe it's pretty easy to test. So, why don't you make the test too? Plug your mid-2010 MBP, let it charge a bit, and put your lips on the case, near the mag zone, or speakers zone. See if it shocks you too. Just comment if you feel it a little bit, or nothin, or a lot. And test the difference with battery and plugged, wich should be no-shock/shock, respectively. Thanks! PS: post your MBP model, and be concrete with the shocking zones please, so if you get shocked on the mag zone and not on the trackpad zone, write it. Thanks! PS2: fill the poll too, after testing as described. edit: well I've seen that it's a comon issue, and it's not about I have this and I have not. It's a recognized Apple issue, and seems that becomes solved if you use this: instead of those: So to make the test, use the adapters please.