The player authors a fiction. The character discovers a reality. How is that hard?
Because then you would likely have to go back and rewrite all of your history to match the newly created reality. Do you, or the players at your table, do that?
Now, when the players encountered the runes, do the players also get to author their
appearance? Or did you do that? Because
how the sign looked should have influenced the PCs' hopes. There's an obvious difference between this:
and this
Just like there's an obvious difference between this:
and this:
If the sign was neatly written and it turns out it's an exit sign, I'd expect that means it was officially placed here--which means there should be
several signs all around the place, because whoever made the dungeon wanted certain areas to be clearly marked. It indicates that the place had a specific purpose that I should see expressed in the dungeon's layout. Which means that in order to keep the immersion, you'd have to retroactively change the adventure so we'd have seen these signs before, and possibly even translated them then. Are you and the players going to do this? If not, there goes the immersion. And judging by some of the people on this thread, the immersion would be gone if you
did.
If the sign was scrawled, then that brings up other possibilities. Did the writer do this to be useful for future travelers? Were they planning on coming back?
Are they here now? Is this sign actually leading to a trap or trick?
For that matter,
unless there was a pointer (on the scrawled sign), why would I "hope" it was an exit sign? If I "hoped" it was graffiti about gladiators/professional pit fighters (which is what the Latin sign actually is, IIRC), then that means there should be evidence of that sort of culture in the dungeon--an arena, training rooms, etc. Which means that you, as the GM, need to incorporate that into our adventure here. Have you?
And yes, as a player, if the GM didn't say whether the runes were neatly carved or scrawled, I'd ask--not as a trap, but because I want a good mental image of the place.