Idiots. All im saying, if done right and safely, should not see why they can't do it. Must be the right area though
That's the point. If any Tom, Dick or Harry were just setting up 'outlaw' games on any scrap of woodland or private land they could find - they may think they are doing it 'right' but they maybe complete retards and they could be doing it 'very wrong' without even being aware.
If you play at a site, the site will be subject to all the laws of the land regarding Health and Safety and registered with the local authority. They may also be a member of the UKPSF meaning they'll have signed up to the code of practise. Essentially, a site will be obligated to do things 'right' and the judgement as to whether they are doing it right or not is made by professionals........not by mates.
Whilst the vast majority of paintball players are eminently sensible and mature individuals, there are plenty of complete tools as well (a reflection of society in general as opposed to just paintball) and 5 minutes on any forum will give you plenty of ammunition to back that point up.
If there was to be an 'incident' whereby a member of the public was injured, or even a participating player was badly hurt, the consequent fall out for the industry in general could be significant and at the very least it would bring unwanted attention.
You can find a walk-on for a tenner nowadays where people can play in a controlled and safe environment. It'd cost you more than a tenner to net an area off, staff it, boundary tape off hazards, complete risk assessments, put up signage, bring in your own legal HPA provision, transport in your paint and keep it in decent condition and the other million and one things that I can't be arsed to list.
Final point, if a participant or a member of the public were injured, the land owner would not necessarily be exempt from prosecution nor civil claim just because he'd rented it to you and you were insured. If one of my kids were injured by a stray ball as they cycled along next some private land that was hosting an 'outlaw' game, I could just as easily pursue the landowner for permitting his property to be used in a way that represented a danger or hazard to the public.
I'll be honest, the above arguments are only scratching the surface.
Paintball isn't a cheap hobby. To play paintball costs money. If you can't afford to pay a tenner to local site owner for a walk-on - then you probably have the wrong hobby. That may sound tough - but it is what it is.