It's not like they would have actually pornography on the site. Also, it's not like your children could PURCHASE the pornography.

Also it would be much easier for your children to get access to pornography through ads, image systems (such as google images) and actual pornography sites (sure most of them, if not all, have that "I am 18 years or older" disclaimer but come on, it's incredibly easy to lie). Also this may shock you but many stores also carry pornography mags.

My point is - while not necessarily "easy" to get access to pornography, if your children really wanted to, they could get it in much easier ways than through Amazon. Of course, I do not know how old your children are.