For sure! The horse in front wether he likes it or not is responsible for all possible dangers. :) Depending on the horse of course, most horses in front are slightly less confident so they feel they have to watch out for things, while if they were following they're content with following the herd. What's neat about trail riding, I have found, is that with each different groups of horses attending they'll follow the most confident horse as its leader. Even if that horse at home is the low man on the pecking order.
Mares, since I have two, crack me up. My two girls won't go in front on the way out and they'll butt-hug the horse in front of them. But soon as we're headed towards home, they're shooting crusties and showing their pearly whites until they're in front! haha. They need a baby sitter in the way out, but when they know where they're going, leave it to them. haha. Mares are fun.
I always really enjoyed watching the horses' behaviors on the trail. Especially if the scenery is boring. :P