Re: Not implausible
It may very well have been a ~2008 Macbook... but it happens with other laptops, plugged in or not, in direct contact or a few inches away. I've experienced poorly grounded guitar amps; that's not it. This feels similar but more subtle, and not immediate.
There are so many variables and alternate explanations ... someone would have to do proper scientific experiments to get to the bottom of this. And I can't see the know-it-alls here doing that. Just as bad as the tinfoil hatters.