As one of the people who brought up having two channels as a solution (that is in fact currently working well for Nature Flight discord), I want to shed some additional light on why I think that second channel has not fallen into the trap you describe:
(1) The list of server-wide triggers is fairly brief and fairly specific to just certain genes and eye types.
(2) The culture around the two channels (and their respective descriptions) makes it very clear that the channel with spoiler requirements should be treated as the default, with the other channel exclusively meant for dragons that could not be posted at all otherwise.
I think (1) is probably the harder, more subjective standard to maintain, and a lot of it comes down to what kind of server culture you're looking to cultivate. An independent FR-themed server will likely have more of an atmosphere of members getting to know each other as people and perhaps even as true friends; in such a context, talking about lots of non-FR topics is expected, and a wider scope for trigger lists is appropriate. For "official" flight discords, though, far fewer "off-topic" (read: non-FR) channels are going to be a thing, making it way more feasible to maintain a trigger list that is comparatively brief and unambiguous.
…Also, it sounds to me like, if one is going to maintain a server where a broader scope of topics (and potential triggers) is discussed, it would be genuinely helpful to go all-in in detail there! That is: (using your example) outright listing the trigger as "moving images of real life butterflies (still images and illustrations are completely fine)." The list is already something people are expected to not be able to memorize, after all; the extra level of detail can only help.
Re: Censoring genes/eye types on Discord
(1) The list of server-wide triggers is fairly brief and fairly specific to just certain genes and eye types.
(2) The culture around the two channels (and their respective descriptions) makes it very clear that the channel with spoiler requirements should be treated as the default, with the other channel exclusively meant for dragons that could not be posted at all otherwise.
I think (1) is probably the harder, more subjective standard to maintain, and a lot of it comes down to what kind of server culture you're looking to cultivate. An independent FR-themed server will likely have more of an atmosphere of members getting to know each other as people and perhaps even as true friends; in such a context, talking about lots of non-FR topics is expected, and a wider scope for trigger lists is appropriate. For "official" flight discords, though, far fewer "off-topic" (read: non-FR) channels are going to be a thing, making it way more feasible to maintain a trigger list that is comparatively brief and unambiguous.
…Also, it sounds to me like, if one is going to maintain a server where a broader scope of topics (and potential triggers) is discussed, it would be genuinely helpful to go all-in in detail there! That is: (using your example) outright listing the trigger as "moving images of real life butterflies (still images and illustrations are completely fine)."
The list is already something people are expected to not be able to memorize, after all; the extra level of detail can only help.