Not at all, doing somthing fun is certainly fine. However I have actually spoken to people (not just on the internet, actually face to face) who are preparing for a zombie apocolypse. Not kidding, not for fun, but dead serious. He explained to me his and his roommates plans. (No girlfriends, any of them) He told me about the weapons they are making. They don't actually have any real guns, but with the weapons they have they can aquire them and are quite certain they can fend off the zombies with their current weapons.
I'm not joking.
It's fine enough to do somthing out of fun, but there will always be those out there who take fun too far. These guys were scary. What you or I call fun these guys call serious. I'll never be able to look at a box of that ammo without thinking how these guys would react if they saw it.