So this has come up in campaigns in my world as well. I’d like to test your boundaries. The heroes beat the gang etc but then want to roleplay threatening say the rest of the gang . Do you allow that?
I change my campaign world to fit my players as 99% of the time I have a plan in my head how the adventure will go and it always fails. We discuss rules as I’m usually impartial. I have redone encounters etc based on circumstances especially if I left something out
For example
-player forgot they had advantage on a roll. We basically redo the roll or they didn’t describe the spell completely and there was something that affected the area etc etc
The players had their torches on but planned on sneaking after but forgot to say we turned off the torch
D&d etc game system isn’t Simon says(old reference so I apologize) . This is a game that impartially needs to be considered all the time and common sense
-no you didn’t sleep with your shield strapped on so when the goblins invade the camp you don’t have your bow notched
But it is your job as the gm to set that expectation for them before.
-you have bill the horse and your going into the tiny cave what do you do with bill and your tents etc
Most of those don't, to me, relate to whether or not a game is a sandbox. For example I'm pretty lenient with small details like forgetting to mention putting out the torches. Occasionally I'll ask for a check because it's uncertain, like whether or not the character remembered to grab something when they had to leave in a hurry. It's a game so I'll handwave little things here and there. If they're bringing good ol' Bill the horse to the mines where even such a brave pony should not venture then they need to figure out what to do with it.
My motivation for not getting too nit-picky is just to keep the game moving forward, it's not to direct the game in any particular direction. It's not even to really help the players achieve their goals, it's just acknowledging that my players are not the characters and that sometimes we forget to mention small things at the table.