So, this bothers me, and it's something super tiny that I run into at p much all levels which makes complete sense to me that I can't seem to explain to other people.
At some point of the game you are going to group up as a team to go "do" something, be that pushing, be that going for dragon/baron. Now your team isn't homogenous, there's some bulk (top/jungle/tank supp maybe some control mage) and some backline (adc, mid mage, ranged support). Obviously there's tons of ways to set that up but the general principle goes. There are people who should avoid getting hit, and there are people who don't mind getting hit for a little, as long as their backline deals more damage.
Now the game isn't so boring that you have to break through the wall before you can kill the juicy squishies. There's mobility abilities, and cc, but most basically, there's: "the flank". You come through a direction that the frontline doesn't cover and the backline falls easily! Now nearly often the obvious direction is the same as the direction of the lane, that's covered. If the enemy wants to flank, he'll have to give up your direct line to their towers/base and have to walk a little longer. There's a trade off.
So why oh why would you position your team in such a way that the most obvious position for them to be in, is also the one they could most succesfully flank from? Why, because someone pinged dragon obviously:
Team pushes up mid as a response, and when they got to the river, they turn right, finding some of the opposing team already there doing scuttle or whatever. Pretty common situation. Now if the x's aren't warded, the backline basically can't walk into the river, they die to something coming through mid, something jumping over the wall, or something hiding in the brush. The frontline then, does not have the damage to back them up, there's no way to win as you've opened your team to a flank. If the x's are warded, the advantage is that you'll know when you can't walk there... but if there's someone standing accross the wall, you still can't actually have the frontline in front of the dragon pit.
More annoyingly, the situation where the frontline has "caught" somebody in mid, who limps out and is escaping into their jungle behind baron. Everybody is running, you don't know where their team is, and the back line becomes opened up to the blue angles of attack, with no cover as they are running after the guy that's almost dead but p much getting away.
And it's like that, pretty much everytime you leave the lane, if you don't have wards beyond where you are in their jungle, you can't actually do it without compromising your formation. You have to walk around.
Surrender, imagine and of course wear something nice.