This is where we differ - and I don't think we can start cleaning up the game until it is done in the younger age groups. Referees are not there to play counselor, they are not there to dictate the pace of the game and they are not there to teach kids the rules. They are there to apply the rules during the match, plain and simple.
A caution is not a tool, it is something given to a player that clearly violates the laws of the game for reasons clearly written in the laws of the game. As a matter of fact, a player on a caution is often times substituted at higher levels when the manager thinks that player is at risk of being sent off, thus putting the team at a disadvantage. When a caution is used strictly as a tool and not as a "one step closer to getting sent off", there is no point in giving it - especially if a referee takes into account that a player is already on a yellow when the next major offense takes place.
Soccer is the only sport I can think of that applies the laws of the game are applied differently based on what age kids are. In basketball a foul is a foul and when you receive 5 or 6 of them, you foul out of a game - other than maybe kindergartners, basketball players don't get an extra allotment of fouls when they are young. In baseball, a strike is a strike (to be fair, strike zone maybe a bit bigger for the little ones), a ball is a ball and an out is an out. In football, a clumsy, slow kid doesn't get to pull the face mask of an opponent just because he is slower and clumsier.
Again, I am very appreciative of the fact that you are out there refereeing games so our kids have a chance to play. However, it is worrisome to me that any referee would take "coordination" into consideration when applying the laws of the game. A late tackle is a late tackle, that endangers an opposing player no matter how "clumsy" a player is. The laws of the game clearly state what the punishment is for endangering an opponent.
Now, I do not want to come across as advocating sending off and cautioning every player age 5-18 the same way across the board, common sense does have to come into play - I think this is where you are trying to make your point. But we need to start somewhere, and that somewhere has to be with the younger players - but more so on the yellow card type of offenses. Sending offs should be the same throughout every age group.
Take the example of a player deliberately elbowing an opposing player in the ribs. If that player begins that type of behavior at 10 (God forbid 6,7,8) and only receives a caution or a stern talking to by the referee, that is not enough to cut that type of behavior out of her game. Once she gets away with only a caution the first time, then she knows she can get away with it again. As the years go by, she has now elbowed opponents 20 times and never has been sent off. Add to that, she is now getting older and a bit wiser, so she expands her arsenal to a little kick out here and there, the elbows now rise to head level, she has begun to pull some hair every now and again and she seems to get away with two footed tackles - when she gets to be 14-15, it is too late to change her mentality. Now, all of this could have been avoided if the referee had the gumption to send her off after that very first deliberate elbow to the ribs when she was 9. I could go on and on about this, but I think you can tell where I am going.
The other thing that bothers me is the fact that someone mentioned previously, you can tell how a kid is being raised by their behavior on the field. Once any kid walks across those white lines, they are no longer in their parents or coaches domain, they are in the referees domain and the players abide by the laws of the game in which the referee is applying or they get to go sit on the bench with the coach. The beauty of this sport is that everyone is treated the same inside the lines. Race, wealth, single parent, two parents, public school, private school, home school - none of it matters, they all play by the same rules during a match.
As for speaking with captains or coaches, it is bothersome that you as a referee has deemed the captains as "more of a figure head." It isn't the job of the referee to decide if a kid is a good enough leader to be a captain, it is the job of the referee to speak to the "captains" each team has designated before the game, during the game and even after the game if needed. If this is done at the first sign of a game getting out of hand, you are correct, there should be no need to ever bring the coaches into the conversation. A very simple chat with the captains such as "listen you two, get your teammates to cut the crap out immediately, or I will not hesitate to go to my back pocket" will go a lot further than you think. Furthermore, if/when you do have to send a player off, you now have the security of already having "warned" each team.
As you can tell, this is a hot button topic for me - and everyone wants the solution to be so complicated or ask referee's to become psychologists. For me it is simple, apply the laws the same way across age groups, from young to professional. When, and only when we begin to do this, we will begin to not only make our on the field product more enjoyable to watch, but we will also begin to develop better players.