What happens if you cut/damage the cable between the brick and the laptop -- which is then sending DC to the laptop? Will that back up the chain and exceed current on the AC circuit? I ask because those cables are usually thinner and more vulnerable. I know mine is looking a little beat. One time my laptop (thin MacBook air) slid off the couch and the nicely machined aluminum edge dang near chopped the chord that was laying on the hardwood floor.
There has to be a better way to get a warm seat than electrifying your recliner.