That wasn't about making it clear or not (I wouldn't have felt out of place posting SFW content anyway), but more about making sure our page doesn't immediately repel the non-sexual part of our potential audience (of which I kinda am, but that's not my point) : we're not a big enough community to allow ourselves to segregate, I'd say. But then I might be wrong. As you said, this is lemmynsfw, and I perfectly expect to have NSFW content within this community's posts. But I suppose the less NSFW inclined visitors would set their Lemmy settings to something like "hide/blur NSFW". Our sidebar isn't going to be blurred to them, and I'd rather have it show something more casual, with less skin (though a little is always ok), maybe something cartoony?
I'm just throwing ideas, sorry if that comes as offensive or anything :/
Here in France, I can't remember ever doing that. And I've had a credit card in francs.