There is a big difference between the following two scenarios:
(1) The PCs, cresting a hill, see a river 150' wide, spanned by a single bridge, with a giant snoozing at the foot of the bridge on their side of the river. Before they get close enough to stir the giant, they retreat back to the other side of the hill to discuss their options. They decide to have the wizard cast a teleport to get all the party over the river and too their intended destination.
(2) The PCs, cresting a hill, see a wide river, with a single bridge, with a giant snoozing at the foot of the bridge on their side of the river. Before they get close enough to stir the giant, they retreat backt to the other side of the hill. They decide that the wizard will cast teleport to get them across the river, so they do not have to either pay off the giant, or fight it while crossing. But to do this requires giving the wizard a round to get into the middle of the bridge! [In 4e, the 10th level spell Arcane Gate can connect to points, each no more than 100' from the caster. A double run let's the wizard move 80' and still have a minor action left to cast the spell.] So the plan they come up with is . . . . [fill in the details yourself].
4e, by removing, watering down or raising the cost of various "encounter bypassing" effects, increases the GM's situational authority. This is one aspect of the game's well-known focus on "the encounter". It is why the DMG has the notorious "guards at the gate" quote - the idea, as I see it, is not that the gameworld will contain no fantasy colour, but rather there is no need for "mere colour" encounters because the meaty encounters will provide that colour. And part of the way they will do that is because the system requires the players to engage with them - even when, as in scenario (2) above, the relevant mode of engagement is to try to avoid a conflict.
I don't see the difference both are methods to handle the encounter. As a DM I know my players abilities so I am aware that they may use teleport if they choose to teleport then they have just used a fifth level spell. Go me, that is a spell they won't have later. I enjoy making magic users use up their spells before they get to the big encounter.
I use little flow charts like what happens if they teleport and miss. I over plan encounters so that if they find away around ones that I expected to take awhile I have more.
If the bridge keeper was going to give them clues about what they were facing then they now are facing that blind.
I have said this before if you don't want your players having the ability to teleport then take it out of the game or add in game reasons that makes it more dangerous. But don't complain about it if it is available in your game and the players choose to use it get around an encounter they don't feel is important. If you really want them to face the encounter give them a reason why. Is the troll killing innocents is the bridge keeper a race of hated foes. It is up to the DM to make players want to engage with the encounters.
In our first 3.0 game we were captured stripped of all our stuff and told we would have to fight in the arena if we lived we would be given our stuff back and escorted to the boundaries of the land that were in.
We shocked the DM who really believed we would never willing leave all our items behind and try to cross a dangerous wilderness without any weapons or items. We choose to run and not fight in the arena. The DM had spent a week working on the arena encounters jokingly woth a hint of frustrations he waved those papers at us and said "this is why some DMs railroad."