So I bought a USB-A to USB-C cable with which you can charge your MacBook through an iPad charger or regular battery packs with USB-A port, and I'm wondering if I can use this cable to charge or power my MacBook from another computer. I often use my MacBook in front of a school computer, and if I can power my MacBook from it like I always do for my iPhone and iPad, I don't have to carry the iPad charger. Given the amount of power a USB-A port of a computer can provide versus the amount of power the MacBook consumes, I don't expect it to be able to really charge my MacBook, but it helps if at least it can power it and extend the battery life for an hour or two. My concern is if it has any potential risk of damage to any of the parties (the MacBook, the school computer, or the cable). Can I have your opinion?