I agree there's a difference between the kind of question like the one above vs. something like 'Why isn't there a check in there before unpacking a record?'
The first question is basically 'Teach me stuff I should know' the second is more along the lines of 'Why do we do it this way?'
And there does come a limit, if after a month they're still asking the same questions, not really seeming to have learned anything, it's probably not going to change.
I dunno, really I guess it usually comes down to the person and I hate to say it but, how annoying I find the questions and the person's behaviour.