A player scouts the big bridge and the DM rolls for a random bridge encounter and gets 'none'. So the PC finds nothing on the bridge.
The player happily has their character go back to town, load up their wagon, and in a couple of game hours goes back to the bridge. The DM rolls another random bridge encounter and gets 'hill giant robber'. So the player looses their player agency by the random roll.
This strikes me as a bit strange. Why would the PC assume that just because the bridge was empty once it would be empty hours later?
Now if they asked the local guides/guards/scouts if there were any monsters or bad guys spotted within a days travel (or did some other more thorough checking that would actually preclude the monster showing up), then that would feel different to me.
It's no different then a DM 'just saying' a troll is 'suddenly' on the bridge.
If they had checked if there were any bad things within a few hours and were told no, then those feel kind of the same to me.
But otherwise, doesn't bad stuff essentially happen at random in real life the way folks often think about it? (Yes, the road home is usually safe, that's why we drive it. Yes there is sometimes a really unsafe driver on it anyway).
It feels akin to the party seeing if it's raining out right now, and if it isn't expecting the weather to be nice for a few days. That feels like that isn't wanting agency, it's wanting oracle type info for no particular reason.
Now, if they actually consulted an oracle or druid for a weather forecast then it should probably stay clear or there better be a reason it didn't. (Say they're heading towards Saruman on a mountain pass and he has spies there and control weather prepped).
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If a party knows that goblins are usually easy to beat, is it removing agency from them by allowing the goblins to roll really well and kick their butts if that how it plays out?
And now, I can imagine a non-DnD system where it might be, and I might have just answered my own question.