if you wanna compliment an artist , ask them about buying one of their original drawings or paintings and frame it up nice.
you are talking apples and oranges , my friend.
artists (generally) live from the sale of thier work. either in selling a print/painting/drawing/sculpture or in selling an image to be used as merchandise , editorial or advertising.
a baseball player on the other hand , is paid a salary. he does not make a living selling his doodles , therefore asking him for one does not devalue his work.
would you walk into a resturant and ask for a free meal as a compliment to the chef?
bottom line , most artists *sell* a commodity you can display in your home and generally that is their only income.
I don't understand "fans". of anything.
I take a sketchbook with me to comic shows and often don't just ask for a sketch. I will buy a couple of books and instead of having the books signed, ask for a sketch in my book. Most often, it's a quick headshot/pencil only. Nothing fancy, but enough to make me happy.
I think it depends. I say, if you buy something, ask away. If they don't want to, they won't.
If they can, they will.
comic cons are mostly a meet and great though aren't they?
and generally , aren't artists flown out by their publishers?
at flatstock artists are flying out on their own dime and generally publish and sell thier own work.
most are hopping to make some sales and gather contacts for future jobs.