Final decision: No content protection features. If it's released, it's free to be used (of course, the expectation of respecting authors' wishes still exist; NeoLemmix simply will not try to enforce this in any way, whether intentionally or as a side effect of something else).
Prompted by an IRC discussion, I'd like to ask how people feel about being able to protect their content from use outside of simply playing it.
In the past, NeoLemmix offered an encryption option for custom content. This is no longer usable for content, and the old encryption code is now used only on the savegame file. However, the primary form of distribution for NeoLemmix content now is everything-in-one EXEs, which have a similar ultimate effect of allowing other users to play the content, but not to, say, open the levels in the editor, or use any graphic sets, etc. In some cases, non-release or delayed release of this content has been used; for example with the Lemmings Plus IV graphic sets, where one of them was released for general use before release; another around the time of the game's release, and the last two not being made available until a while later.
By comparison, other engines don't really offer any such equivalent. Lemmix does have the possibility of making an all-in-one EXE, but unlike with NeoLemmix which has the dedicated Flexi Toolkit, it's quite a mission to actually do so, and as such there's only four cases I know of where this has been done - the pre-NeoLemmix versions of Lemmings Plus I, II and II Bonus Pack (which have now been replaced with NeoLemmix versions), and cLemmings Ultimate Edition. Lemmini, SuperLemmini and Lix offer nothing of the sort; any distributed content can be used by anyone in any way they like. (To be fair, someone determined enough could extract the content from a NeoLemmix all-in-one EXE if they really wanted; it's just not as straightforward as in other engines where the file is right there and can be opened with the editor / etc.)
So my question is - do people feel that this is an important feature of NeoLemmix? Or is it mainly used because "that's just what happens when the most common method of distributing content is used", without people really caring too much about this? I ask this because, I absolutely will preserve such a capability in some way in NX2 if there's demand for it, but if people aren't too interested, I probably won't do so.
Keep in mind that any such measures wouldn't be overly hard to defeat, especially given that NX2's source code will be available, so someone technically-capable enough could either examine that to work out what triggers such measures and modify the files to get around it, or alternatively, just produce a modified copy that does not comply with restrictions. But it might be enough of a deterrent for people to think it's not worth bothering, and also, generally speaking, the kind of people who'd be likely to want to bypass such restrictions in order to actually try and use the content are also likely to be the kind of people who wouldn't be able to work out how to do so.