Ovinomancer
No flips for you!
I tend to agree, however 5e is written in a general mess such that it's sometimes rather hard to disentangle whether or not something is a rule or a suggestion or just discussion.I would say “all text in the rulebook is rules text unless otherwise stated” is a more sound assumption than “some text in the rule book is not rules, but it is not explicitly indicated as such”.
In the case of the blurb under Roleplaying, it's not very clear that this is a rule. For one, it certainly doesn't cover all kinds of roleplaying that are possible in RPGs, much less 5e. It's a decently general statement. Second, there's no place where roleplaying is called out as present or not present in any given situation -- ie, the game doesn't state when roleplaying is expected to be engaged. Clearly, I'm not roleplaying when I'm creating a character, yet this is still part of playing the game. So, we have that ambiguity. I don't disagree that in the topic at hand roleplaying is likely involved, but, and this is critical, if we're criticizing a logical argument we have to note that this is assumption, not fact. We are assuming roleplaying is controlling in some way here because it's not said otherwise. This is what's smuggled in via assumptions and prior experience with RPGs.
The second statement counteracts the first, though. I can very easily decide that being a friendly acquaintance in this situation is violently and repeatedly ramming a blade through the caster while hurling vile obscenities about their ancestry. And frothing at the mouth as if in a rage. This is me deciding what friendly acquaintance is here. If the definition of a thing is left undefined in this way, then there's no teeth at all to this effect -- I can, quite literally, decide to do whatever I want.So, two things. First of all, I disagree that Charm Person is not clear that it’s an exception to the player’s ability to decide what their character does. It explicitly says “If [the target creature] fails the saving throw, it is charmed by you until the spell ends or until you or your companions do anything harmful to it. The charmed creature regards you as a friendly acquaintance.” That’s an explicit statement of what the affected creature does, which indeed contradicts the general rule that players decide what their characters do.
Second, I leave it up to the player what it means for their character to “regard [the caster of charm person] as a friendly acquaintance,” the same way it is left up to me to decide that for NPCs.
Further, using Persuasion successfully has a listed effect in the PHB that is as binding as the Charm Person example. I think that there's some other smuggled assumptions in, primarily around the idea that "magic" is somehow special, that the spell has a clear effect while the ability check does not, but there's about equal weight of words and clarity of effect in both. The DMG social encounters rules also indicates that a successful Persuasion can improve the attitude of the PC -- something never assigned and so having about as much impact as the Charm Person spell.
Taken directly, there's no real evidence for either being more or less functional than the other. So, even if we assume Roleplaying is in effect, the difference between a successful CHA(persuasion) check and a failed save vs Charm Person are equally binding on the following play. Which is to say, not very much by the rules. It's the smuggled assumptions that tip the scale, and the impact of the social contract at the table. If a GM used NPC CHA checks on the players and then vetoed action declarations that didn't agree with the GM's idea of how the PC should react, this seems exactly like the result for a Charm Person spell. There's a good reason I do NOT allow NPC CHA checks against PCs (or PCs vs PCs) and very much shy away from use of Charm spells vs PCs in my play -- they step hard on the one place that 5e actually carves out agency for players. I dislike stepping on that, so I don't, and am explicit about it. I don't think the rules particularly support this, or particularly oppose it. It's just good play for me. Others can differ. The rules don't much stop them, either. The beauty of 5e is really in how they avoided making any real stands on how the game plays in large part, while hiding the strong stands they made in other areas.