They can filter the parts library, but if Little Johnny heard of something at school and made his own design, I don't see how the system can prevent that short of a parental lockout / corporate approval system where every printed part must be approved before printing. Even then, the most determined hacker-kids will figure out how to subvert that system.

It looks like it only has a small set of built-in models, then the rest are file imports from somewhere on your machine. It doesn't seem to connect to an online store of models at this point.

I hope you mean 'things like guns' but I fear you mean 'things like dicks'. Meanwhile most of the workforce brings his dick to work while the guns stay home as they are 'not safe for work', as it should be. This is clearly an area were reality comes out ahead...

I never thought of 3d printing in that way. Inevitably someone will work out how to have sex with something.

3D printed sex toys already exist.

I suppose an advantage of them is there's no embarassment in purchasing them, you can tailor them to your body, you can choose colours, etc.