Here's an example of what you've just described. It's from my own TB2e play:
Conversely, here's an (imagined) example of the players having to act surprised when they're not. It could come from any version of classic D&D (eg OD&D, B/X, AD&D, etc):
*The GM rolls for a wandering monster, and it comes up positive.
*The GM asks the players to roll for surprise, and rolls for surprise for the monsters;
*The players' roll indicates that the PCs are surprised; the GM's roll indicates that the monsters are not surprised;
*The GM rolls for a reaction, and gets a response that indicates that the monster's attack the PCs;
*The GM tells the players - "The monsters attack you, with surprise!"
In this situation, of course the players aren't surprised - they've seen the GM rolling all these dice, and they've been asked by the GM to roll their own surprise dice. But they have to "pretend" that their PCs are surprised, and the mechanics - which forbid them from taking actions, enforce this.
Classic Traveller uses a slightly different way of handling surprise, but it could play out in a broadly similar fashion.
But has anyone ever argued that the surprise rules in these well-known, well-established RPGs are an obstacle to roleplaying or a burden on player agency?