It's not the altering of reality that would bother me. It would only bother me if doing so invalidates player choice.
If you don't invalidate player choices or force meaningless choices on your players you can do whatever you think is fun.
So those pre-planned encounters? If I never had any knowledge of them and the DM decided to use one (that he/she meant for another area), I wouldn't consider that a problem. It doesn't invalidate any choice I have.
If on the other hand I'm offered three choices on where to go, but no matter which choice I take I'm going to end up encountering the same encounter... that is a problem. It means my choices were meaningless.
As a DM I have a list of pre-planned / pre-designed encounter areas and lairs that I will use as a result of a random encounter table. These encounters are set pieces that are meant to stock empty hexes or as possible locations that are discovered when the players tarry on, in an area.
Using them doesn't invalidate player choice because they are not integral to any plot nor are they forced. They can be avoided and once encountered they are set in stone in the world. They don't suddenly reappear somewhere else just because the players decided to avoid the encounter and I decided to reuse them.
If you don't invalidate player choices or force meaningless choices on your players you can do whatever you think is fun.
So those pre-planned encounters? If I never had any knowledge of them and the DM decided to use one (that he/she meant for another area), I wouldn't consider that a problem. It doesn't invalidate any choice I have.
If on the other hand I'm offered three choices on where to go, but no matter which choice I take I'm going to end up encountering the same encounter... that is a problem. It means my choices were meaningless.
As a DM I have a list of pre-planned / pre-designed encounter areas and lairs that I will use as a result of a random encounter table. These encounters are set pieces that are meant to stock empty hexes or as possible locations that are discovered when the players tarry on, in an area.
Using them doesn't invalidate player choice because they are not integral to any plot nor are they forced. They can be avoided and once encountered they are set in stone in the world. They don't suddenly reappear somewhere else just because the players decided to avoid the encounter and I decided to reuse them.