"In other words, anyone could cook up a batch of your DNA to spray around a crime scene...Can anyone confirm this is possible?"

Of course it is possible and much easier than "cooking up a batch.

Collect hair from your hairbrush, dandruff, etc. Collect used tissue papers you have used to blow your nose. I guess the latter you WOULD soak/dissolve for a spray but I'd scarcely compare the effort needed to that of producing "bathtub E".

Yes, it's possible to replicate DNA - and necessary for research purposes, etc. It is reasonably easy, with the right training; it is also quite expensive. But from that to the production of Insta-Evidence.... it's a bit far-fetched, I think. DNA does not keep very well outside the fridge, and has annoying tendencies to shear. For this and other reasons, I don't think it would be easible to spray it on anything!

I do believe there are many worrisome things about DNA data banks and use of genetic info by police, employers and insurance companies. There's no need to make up these kinds of things to stress people out even more...