During most outdoor games I've been at or watched the organizers form teams by uniform patterns (e.g. multicam + M81 vs Marpat + solids). The team patterns are often published in advance to allow people to wear matching clothing and be on the same team. (as an aside, I’ve never seen this rule applied indoors for some reason)
This rule doesn't work due to the trends that are found in airsoft. Some of the current trends include the almost ubiquitous use of AR replicas and the popularity of multicam. Since a large portion of players wear the same pattern, teams tend to be unbalanced where most of the players are on the team with the trendy pattern.
To respond to this imbalance, refs often change the teams at the last minute which defeats the purpose of organizing by uniform in the first place. In addition some patterns perform better in certain environments than others, which pit the players wearing effective patterns against those with ineffective patterns. If you’re playing in the woods with a team that wears moon camo, you’re going to have a bad time.
How many people can you see in these images?
Lastly if you brought friends to the game with different clothing from you, you’ll be playing against your friends whether you like it or not. To play with your group, you're forced to buy matching clothes which is just another unneeded expense.
Instead of grouping players by pattern, players should have an armband or some other dedicated device to show what team they’re on. This eliminates the confusion that can occur if you forget which team a specific player is on due to what they’re wearing. This also takes care of any imbalance issues that may occur, you can easily add or remove players by giving out new armbands.
