I've had two challenge ideas floating around in my head for a while. I'll spare the details but as a general overview:
The first is a challenge that should, in principle, be fun but in practice it is so easy for cops to make solutions that are virtually impossible to crack that it couldn't be fun in practice. Similar to how it is quite easy to make a riddle that no one can crack, but hard riddles are not good.
The other is not really even a cops and robbers question, but would involve collecting OEIS sequences (and some other information) submitted by users and then having a competition based on the submitted sequences. There can't rally be a winning criterion for OEIS sequences.
Here there seems to be a common thread. I would like to post a two thread (cops and robbers style) question that is competitive and does have a winning criterion but only for one thread. In the second case the goal of the non-scored thread would be to maximize your own score on the scored thread, but the first is in even murkier water where the ostensibly the only goal of one thread is to make the other thread "fun" (whatever that means).1
Now perhaps each scenario should be treated separately, but they are similar so I thought I'd put them as one meta question.
Can a two thread challenge have one thread without a winning criterion? If so what restrictions should we put in place on such challenge types?
I have thought of making it a pop-con and robbers but I really, really don't like pop-cons for a number of reasons, and I'd rather not ask the question than ruin it by making it a pop-con.