What's old is new again, but I welcome this.
I used to do this 15 years ago to keep listening to music from my laptop (one of the white chiclet ones) in my backpack, can't remember the name of the app I used then.
One caveat, your laptop cannot cool inside a backpack, it will overheat and shut down anyway. This happened to me several times.
had a coworkers whose laptop keys melted into mush
It has a setting for thermal cutoff that you can set to something like 60º C. Sleeping will stop heavy work (like a build) before it leads to overheating.