Comic Convention Booth question: When making fan art with posters and merch, should you worry about copy right law suit?

(discussion & advice)

I'm planing to get my own comic booth this year. I have a line up of posters, fan art and personal work. That i'm planing to sell.

This year i'm also planing to make my own t-shirt brand for the shows, fan art base shirt. But I am concern if I should worry about copy right laws. If a suit that representative from company shows up at a con and tries to shut me down. Which I doubt.

What should I do, what should I know or is there no need to worry?

Please give me your experience.