I'm torn between agreeing with all of you and disagreeing with all of you.
I should start by admitting that I don't personally have a problem with the way it's being done now. I think that as long as we are all careful to not make gratuitous core changes and only put in things that really need to be there, it won't get out of hand even when there are multiple special cases in the future, and probably isn't worth all the extra effort we're going to have to go to to avoid it. But I am clearly in the minority in that opinion.
My first reaction to the service contract idea was the same as Don's - they are too complex for the benefit here. I am also concerned that we'd have a proliferation of service contracts that were only implemented by one package.
However, I don't really like the suggestion to re-implement the offending page in dotlrn, either. As Torben points out that's what we did for registration in e-commerce; it has worked ok for the site it was done for but it has been a headache for others, including Torben, ever since. So I'd rather not go down that road if I can avoid it. This particular change may warrant doing this, but I don't think we should be encouraging people to duplicate code as the official way to handle this situation.
I'm trying to come up with a better suggestion to offer but so far nothing is coming to mind, probably because I think checking to make sure that dotlrn is mounted (not just installed, since that doesn't imply that it's in use) is the simplest and cleanest way to handle this. I'm still thinking about it but I wanted to add my thoughts so far to the discussion.
