@Xenograg
I don't get why you're rolling to check for traps for the player behind the screen.
Why isn't she rolling?
If she was rolling she would know she rolled low and your answer of "no traps you can detect" would be sus.
She could then either not open it, or ask for a fellow PC with decent investigation to look at it with a higher DC.
That's kinda the point of dice, and why it's funny when people roll low. They still "think" they're fine but the player knows she may not be.
@Xenograg
I mean...
"She rolled very low, and in turn, I told her that there were no traps she could detect."
She knew she rolled low, you said no traps "she could detect".
Rules as written the player knew the character wasn't sure, and opened it anyway.
At my table she takes the poison.
Because she could have decided to not open it, or asked another player with decent Investigation to give it a 2nd look with a higher DC.
I take it easy on my players but that is why we do dice rolls.
@Xenograg Very interesting! I see where the author is coming from for sure.
My first instinct to solve the author's problem is to let players know there are traps without a roll, but to have to roll in order to disarm. Can also tell them whether they disarmed it or not, so the decision is effectively "okay this isn't trapped" or "it is trapped, do we open it anyway or do something else"
@glitchcake@Xenograg The thing that jumped out at me was that the poison was exceptionally deadly. That doesn't seem like good design to me. A simple trap ought to be a nuisance or cause some complication, or at the most boring, cause minor injury; it shouldn't outright kill a character.
@Xenograg@glitchcake The dungeon builder presumably doesn't have infinite resources, and doesn't always get to use the best possible means to their goal, right? That's how I'd rationalize it.