For good questions of "is it legal", these were never on topic on Programmers.SE and if Law.SE wants to have them, by all means let them have these questions. This is especially true for questions of patent and trademark which are even trickier for a layperson to answer than copyright (which we deal with in licenses).
For questions of licensing, there are a class of these which we consistently close: "is there a license that meets these requirements." If OS.SE wishes to have the well written questions of this form, again, by all means let them have them as they would be closed as off topic here.
For licensing questions that we, as a programmer, have sufficient expertise to be able to properly answer, these should remain on topic here. This does make for that fuzzy line between P.SE and OS.SE to which the rubric that should be used is "does an expert programmer have knowledge to answer this, drawing from the experience as an expert programmer?" If so, it is still on topic here.
There are many questions however, where we, as programmers don't have expert knowledge in the area. Some examples of these include:
- http://programmers.stackexchange.com/q/286968/40980Are Microsoft fonts like Impact safe to use in Open Source projects?
- http://programmers.stackexchange.com/questions/267162/licensing-cc-by-sa-to-cc-by-nc-saLicensing: CC-BY-SA to CC-BY-NC-SA
- http://programmers.stackexchange.com/questions/147111/what-is-wrong-with-the-unlicenseWhat is wrong with the Unlicense?
- http://programmers.stackexchange.com/questions/250259/does-cc0-allow-sublicensing-of-derived-worksDoes CC0 allow sublicensing of derived works?
These are questions which delve much deeper than a programmer is expected to have expert knowledge in and needs an answer from someone who is intimately familiar with licensing and intellectual property rather than facades and mvc.
So yes, there are certainly licensing questions that are out of our realm and should be migrated to OS.SE given that they want them (just as there are questions that involve database design that go much deeper than the expert programmer is familiar which we migrate to DBA.SE).