Seems like many large groups put the newer riders in the rear and mostly with no mirrors. And if they do see you they don't know what to do and are afraid of losing their group.
I agree. When riding in a group with less experienced riders the two "best" (not only experienced but responsible and aware) should split the duty of leading and bringing up the rear to make sure everyone in the group is accounted for and sets a decent pace for the middle. I find most(not all) newer or less experienced riders are too intimidated to ride fast and hang back, which is fine(and encouraged) as long as there is someone who knows whats up following them and keeping them on track with a steady pace. Its the guys in the middle of the pack you usually have to watch for as they get a sense of false security that they can ride as fast as they want so long as the leader is in sight. It seems like 9/10 times its not always the leader but the 2nd, 3rd... guys that always are hugging the inside corner trying to keep pace with Dad or their buddy who has years of riding experience that end up sideways in corners or, in some cases, head on in your lane. In this case that is the lead sleds fault for not knocking their helmets together at the next stop when they see this reckless driving happening behind them. The same goes for the last rider in the group when they see sleds behind them that are politely trying to pass. It should be communicated to the new riders, before the ride, that they need to be aware of whats going on behind them when it is safe to do so. I can't say how many times I have tried to get the attention of the riders in front of me only to be oblivious to them with little or no safe opportunity to get their attention. In that case it is the experienced sled in the backs fault for not having a clear understanding with the newbies that they need to look behind them and make sure the guy in the rear is not only still there, but also that he is not trying to tell him or the riders in front something. These things are common sense to most but it seems to happen every time I go riding.
Bottom line..Smooth trail, rough trail, wide trail, narrow trail.. it doesn't matter! You have to pay attention and be on your toes ALL the time when snowmobiling. Ride defensively but also relaxed. Ever wonder why professional racers make it look like its easy to maneuver a 500+ lb machine around a race course? Its because they practice and master all of those things and are comfortable and in control of their machine. Of course I am not suggesting we all become overly confident and try to ride like a racer (thats a whole other story), plus racers don't have oncoming traffic coming at them (hmm..that would be interesting to watch though!)..but I hope my point is made. If you feel like your having an anxiety attack on every ride, its most likely because you are riding out of your abilities. When that happens it is very likely that someone is going to get hurt..or worse!