These wireless mouse has those small usb receivers, they are not really strong. When you put your notebook into the backpack after using this you can be a good user and store it inside your mouse or can be lazy and leave this receiver into any of usb connetors of your notebook.
If you choose the lazy option, you can have a terrible problem, if you leave your mouse receiver on the underside of your notebook, the impact of weight of your notebook over your mouse receiver can destroy the head of this component.
What you can do ? simple, you can protect it with Sugru !

Step 1: Mold Your Receiver Protection.

Involve your receiver with sugru, caution with that because it will never fit into the receiver holder inside the mouse again. Try to mold around the receiver with any instrument, you don't have to create a ball around it, its only a protection, i've made a square hole to see the receiver brand inside it.

Step 2: An Clue for Final Mold

After mold your receiver protection, put it into the receiver, it have to
join in onto the notebook usb port, to support the protector. When it hit into the floor or into de underside of the backpack, the impact goes to the notebook frame, not to the mouse receiver.
Its not a problem hold the receiver all the time on the notebook, after sometime you forget it's there.