No, there is no training or licencing for paintball markers.
I'm not sure if they ever officially started using paintball for training, but units were using paintball gear they bought with their own money since paintball was available.
There aren't any (non military) training places for paintball. The best way to improve is to listen to older players and play as often as possible.
President Barack Hussein Obama.
Actually yes in some cases. Kingman released two new paintball pistols, the Chaser and the Eraser. These have been very popular for hand gun training not only in the military but in law enforcements.
Not with paintball guns, no. There is some use of Simunitions for urban warfare, but those are modified upper receivers on standard lower receivers. Paintball guns would be useless - hopper capacities don't reflect magazine capacities, the ergonomics of a paintball gun don't match the ergonomics of a service rifle - they'd have little training value, especially when an important part of the training is to familiarise yourself with the weapon you'd be using in combat.
The military, when not using simunitions (chalk like paintballs used in actual firearms) , uses paintballs for training.
One can find discounted paintball accessories from Just Paintball, Paintballing, Discount Paintball, Zephyr Paintball, Outpost Paintball, Paintball UK and Armed Paintball stores.
Paintball is used by several militaries in training, including the US and GB. Paintball is not a perfect simulation of war by any standards, but It is preferred by many over laser systems or blueguns, because of the actual projectiles used, and their relative low cost.
Popular paintball stores in the US offering discounted paintball equipment include Paintball Discounters, Paintball Online, Discount Paintball, and Zephyr Paintball. Inexpensive paintball equipment can be found secondhand on websites such as Amazon and eBay.
The purpose of a paintball gun is to fire paintball pellets, to mark opponents in the game of paintball.
a paintball arena is an indoor paintball field where they usually play speedbal