Except that the availability conditions are a plugin type, so if this is wanted it could be developed as a 3rd party plugin
in your opinion, would it be easy or difficult to enable the build-in password functionality (as used in quizzes and lessons) via an easy tweak of the php code?
I don't know the answer to Hiram's question about ease of enabling, but I do like the idea of having a password for an assignment (built in) or having an availablity condition of a password - let's hope someone clever sees this and makes one
For someone who knows what they are doing, it doesn't look all that hard to implement a conditional access restriction - unfortunately that's not me right now. It's not an area I have looked at the code of in detail and currently would not be able to do this until late summer at least, by which time Im sure someone else in the community would have been able to pick this up and come up with a solution.
I do though, think its a great idea and would love it if someone could implement it!
As for recoding the assignment itself to have this feature, someone like Tim Hunt would probably be better person to ask what's involved as I presume he would have been involved in the quiz one, but I would imagine its a bit more than a simple php tweak.