That's fine, but then you must follow through on that courtesy by having the actual question ready to paste and send when the person says "yes". By taking more of their time, you're being rude, not courteous.
In my darker moments I think people don't want to take the time to type a good question and only commit to it when they believe I'll be faster than grep/google. Not sure if they realize that now I have to sit through that typing time in addition to providing help.