[Liftyee]

Can confirm it does happen. UK, both on my ThinkPad and a friend's MacBook when plugged in. It's a somewhat unavoidable side effect of the switching AC adapter designs - the output is isolated from the mains, but there is a tiny leakage current that can sometimes be felt as a "vibration". This is completely safe (far below the currents needed to cause harm) and no recall is needed.

[cachius]

Thank you. I always felt this vibration and wondered what it was.

[mapmap]

If you replace the two prong plug on the AC adapter for a three prong cable, your MacBook case will be properly grounded and you won’t feel any vibration.