I was thinking about bringing it in to the ring fully charged, then what if it shot off accidentally. It would be time consuming to pump it and set up once in the ring. Maybe not though. You do have to practice proper firearm protocol. you could maim someone with that thing if your not careful!
It should NOT be pumped up prior to entering the ring. It does not have a "safety".
Let's say the operator tripped, fell, and the valve opened.
Even if the cylinder only had small pieces of debris (sand, dirt, chips, etc) they would be shot out a very high velocity.
I ran the throw-line event at the TreeStuff Jamboree.
We did not allow it to be charged before entering the ring.
One of the nice things about the APTA is the same thing that everybody complains about, it doesn't have a trigger. The valve handle needs to be opened up in one continuous quick movement for it to develop enough force to launch the throw bag. If you accidently bump the lever partly open, all the air just fizzles out with no oomph. I feel after using one for a couple of years that it is not only more accurate than a bigshot but also safer.