A general question about open-source licenses: I know you can't modify them yourself (i.e. "GPL except you can't do this") and writing your own is generally a bad idea. However, is it feasible to add "Please do this" riders?
For example, say that I want to license something under the GPL. Can I add a clause which says
"If you release a fork of this software, you are hereby requested to contact so-and-so and notify them"? Would this count as a different license? For that matter, is the license even the right place for such a request, or should it go in a README (and if so, how would you get it to propagate)?
Edit: To clarify, I'm primarily asking whether this is something that can be done, and only secondarily whether it's a good idea (I suspected not, and the first responses confirm it). I have no intent of actually doing so, it's just inspired by an unrelated discussion I had.