If you do it legally you will have log it. There will be a paper trail that you lumped the load and didnt log it...
It will eat your clock. Or you will start your clock if your trainer happens to be in the driver's seat at the time of Recieving. Most cases you won't be able to do it faster.
Unlessnyou got some sort of liscense or certificate, I can't think of a single receiver that will let you use their powered equipment.
Just because Prime will pay extortionate rates the lumpers request, doesn't mean they will pay you that amount. It's a set rate in the employee handbook, and it really ain't that great.
There is a greater risk of on the job injury.
I'm pretty sure your trainer will frown upon it. You are there to learn... Get that done, then you can do your own thing.
What U2 said - its not worth what it will do to your 14 and 70-hour clocks, certainly not worth what Prime will pay you to do it, and the risk of injury can finish your driving career. The worst part is that for a little money, you end up getting tired - then have to drive afterwords. You're taking the risk of getting into a fatigue-related accident. Better to invest your time in a nap.