I write non fiction books about computer science and security (Zzz) but with the security bits in particular, do I really need to put a disclaimer saying "hey don't go hack the government" on my ebooks?
Could some reader potentially turn around and say "you didn't warn me stealing credit card information is illegal" and try some frivolous lawsuit? - I constantly find myself reading and writing these little "don't use this in the real world" messages and its becoming cumbersome.