You have to cater for the lowest common denomiator. [...]
No-one else fancy contending this?
While I agree that, as a designer, you have a responsibility to provide an interface solution that ideally every user will find intuitive [or at least one that's easily learned], I'm also of the opinion that the users themselves have
some responsibility for their actions/decisions:
http://unitinteractive.com/blog/2009/05/18/usability-vs-thinkability/
As Trip points out, putting a '?' next to a 'submit' button is rarely - if ever - encountered; users, through experience, know what a 'submit' button does. That particular aspect of web interface 'language' is encountered and learned very early on in website use; so much so that interface designers the world over can say with confidence that a '?' to explain a 'submit' button is redundant.
Extrapolate to the natural conclusion of "catering for the lowest denominator"-based design, and you'll soon realise that having to explain everything is not only unnecessary, but harmful to the overall interface: explanations of hyperlinks?! Isn't that a bit ridiculous? Of course it is, but the principle is exactly the same.
In other words, a designer
has to make some assumption that the user has some knowledge, and responsibility for applying that knowledge, when designing.
It's encouraging to see others realising the importance of "don't make me think" interface design, but only Trip fully appreciates the context of the problem here. If it is
guaranteed that users encountering this calendar paradigm will have encountered something very similar before, then I think he is right to question the need for further aids.
Additionally, if the calendar paradigm in question is part of a procedure that is less important than, say, booking flights, then maybe further explanation really isn't as vital.
However, I suspect that there's also an element of "I resent the fact that you want to pollute my aesthetically clean, neatly arranged layout that I've sweated blood over". Correct me if I'm wrong, fellow designer
Of course, the only way to truly find out whether a '?' is necessary or not is to test it out, as any responsible design process should.
So to answer your question directly, Trip, you are both wrong and not wrong, like
Schrodinger's Cat, until you open the box and test. Which you should have been doing anyway