Seeing
@iserith make a save did cause the other players to decide their characters would not partake, yes. But nowhere does it say that the players had previously said their characters would partake in the first place, therefore the players “changing what their characters would do,” as you put it, is not expressed in the premise. It is entirely possible that the players wouldn’t have had their characters to partake
anyway; indeed, I don’t think I’ve ever actually seen PCs eat food offered by an NPC.
Really? That sounds absolutely bizarre to me. If you've already come to the table, refusing to eat the food is just a really odd thing to do--and in cultures where the guest right is of extreme importance, a guest being rude about your hospitality is a major no-no. (Consider the cultures where it is considered rude
not to belch or break wind after a meal, because that's how you show you
enjoyed it!)
Moreover, even if seeing iserith make a save did make the other players choose differently than they otherwise would have, so what? If the action is reasonable for the characters to take without that knowledge, who cares that the players had it?
First: I don't actually accept that this action
is reasonable, for the reasons given above. Blanket refusal
without any reason given is, at the very least, something that should require an effort to save face or avoid giving offense. And unless they really do already have an honest reason for not doing it, passing off a fake reason sounds like some kind of bluff-type check to me. It's certainly not something I would expect to go unremarked.
Second: I believe that intent matters with an action. Seeing someone else make a save and then
suddenly everyone is putting as much distance as possible between themselves and that fruit? Yeah, that's kind of a dead giveaway that the
only reason it's being done is because the players gained knowledge the characters couldn't possibly have. When possible, I prefer that such decisions have a
reasonable relationship to character choices. That doesn't mean a perfect mapping, because we accept abstractions. (E.g., I have no problem with "daily powers" for non-magical characters, because I accept that that is an abstraction to enable useful game design space, and because I accept things like "bennies" and other meta-currencies.) But when one is very literally predicating a purely roleplayed action (such as eating or not eating fruit)
specifically on the fact that a gameplay interaction occurred, that bothers me; unlike the meta-currency case, where there's at least a tenuous relationship involved, there's
no relationship involved here.
Want to roleplay being eagle-eyed and trying to catch the signs that your friend had some gastric distress? Do so! Actually take the
effort to give yourself a justification. That effort isn't hard, and odds are good at least one person in the party is more circumspect and chary-eyed than Iserith's fruit-eater. Just...don't pretend like "I saw <Player> make a saving throw! I don't want to do the thing that made him make a saving throw!" is in any way the same as, "I saw Binro nearly throw up for a moment before things settled down, I'm not sure I want to eat that fruit!" The former has no relationship between the input (<Player> made a saving throw) and the output (<My Character> refuses to eat), while the latter does relate its input (I-as-<My Character> saw Binro nearly throw up) to its output (I-as-<My Character> refuse to eat.)
