If you want me in person, you have to disclose the agenda

A friend has been trying to see me for 2 weeks, needs to see me in person but will not tell me what it’s about.  This happens a lot. Unless you are paying me by the hour you are not allowed to ask to see me in person and not tell me what it is about. Even well meaning friends will do that to solicit me.  I always have several projects going at once, and I prioritize them daily.  I’ll entertain ANY idea you want to share but you have to email me. I want it in writing to read at my leisure. I’m just saving us both time so we can get to the heart of the matter as soon as possible since we’re both busy. You putting it in writing will also clarify any initial questions you have, just as an initial conversation with me would do.  I look forward to hearing your ideas.