Most fields would ask that you have a trigger guard so that you do not accidentally discharge your marker while not playing. However it is up to the Referee of Field manager to say what markers and modifications you can play with. Check before trying to play with it, and to be on the safe side, put one on anyways.
No, there is no training or licencing for paintball markers.
Generally speaking, no.
It is not recommended you do this for safety reasons.
On most if not all paintball guns you would have to pull the trigger with the safety off.
You need to be more specific with the problem with the safety, and what kind of safety it is.
It depends on who you are borrowing it from.
Yes you can! You have to wear safety googles and be next to a parent.
The purpose of a paintball gun is to fire paintball pellets, to mark opponents in the game of paintball.
A paintball marker is a paintball gun. It is just called a marker instead of a gun.
No, do not expose your paintball gun to water.
No. The state of Ohio did not invent the paintball gun.
A paintball gun is several magnitudes stronger then a Nerf gun. A paintball travels at around 200 mph, where a Nerf gun is around 10.
No. Nothing dissolves in the process of a paintball gun firing.
11 to play at fields, 18 to buy a paintball gun.