Yeah my entire family knows, especially since I majored in children's book illustration. I used to print out and send short stories and newspapery comics to my nieces and nephews (My bros are a lot older than me so I have 9 neices and nephews). They loved it and are very bummed out that I don't do that anymore. I don't think my parents read my webcomics, but they know I make stuff, and I talk about it on twitter for the world to see.
Overall, my family does not care, they're just happy I didn't get pregnant at 16 and do hard drugs. I was the easy grandchild. Like...kids can have some real serious problems. Be glad if the worst they do is make a kinda silly webcomic.
As for burning stuff though--I feel like that only encourages children to do it more. I'm pretty sure they've done scientific studies on that (not on comics specifically, but you know what I mean), and while it's been a while since I took psych classes and learned about child development...that treatment tends to backfire.