Ahh, there's that word again - cheating. I love loaded words, they do a marvelous job showing a position's true colors. Here's the deal, the players can prefer whatever they want, and they have every right to be upset if they realize that things are being moved around - deus ex machina sucks. What players don't get to prefer is how I prep and run a campaign. In that case they might prefer to run their own campaign. If I reorganize a bunch of my stuff after an unexpected hard right by the players that's no one's business but mine.
The extent to which I rearrange things, and what things I might rearrange are precisely where the campaign contract and player expectations come in. In a game more like the one iserith wants, I wouldn't move encounters no matter what the PCs do. What I might do is either deploy a floating NPC I had prepped for just that situations, or create that NPC on the fly to do the same job. Or, if it didn't matter much, I might not move anything. In a different kind of game, I might just move a couple of encounters to the new location if it made sense, or maybe not move anything and let the side game play out. It's all about consistency in the fiction and what makes the most sense in the moment.