While making money is almost certainly the driving force behind "field paint only" policies, another major reason is quality control:
pblvr22574, on Mar 7 2010, 06:56 AM, said:
... certain restrictions like no monster balls excessively thick shells or red fill...
Big Bone, on Mar 8 2010, 03:01 PM, said:
Over all it makes it more organized, clean cut, and equalizes at least one aspect of playing paintball. If you have to play with crap paint at least everyone else does too.
Restrictions on certain brands & fills is admirable at byop facilities, but it can be difficult to police. The problem is that inevitably there are going to be players that had their Mom drop them off at Wal-mart on the way to the field & the paint they buy is going to be garbage. They figure saving $25 is worth it, but we all know better.
As an example: Battlefront Paintball
, as far as I know, has always been a fpo field. The problem is they used to offered 3 grades of paint (plus winter grade during the cold months) & all had different combinations of shell & fill colors. They were always on the lookout for smugglers but again, it's difficult to enforce something when the refs couldn't always be certain if the paint used was actual field paint. A year ago they contracted w/ RPS for custom paintballs... yellow fill for all paint w/ yellow shells for basic, yellow & pink shells for premium, yellow & red shells for winter grade. Makes spotting smugglers trying to shoot green monsterballs easy. Their prices are pretty decent too - it's $57 for a case of basic, $65 for premium & $68 for winter. You can use any of it all year round if you don't use it all the day you play.
I think the point you made Micah is spot on. When it's an fpo facility, the "playing field" is even. Everybody has the same quality (or crap) paint to choose from.