You were worried about someone using LLMs to make weapons. So I went for the ones that are more realistic. Bioweapons are far harder to make than chemical weapons. The science is harder, the actual synthesis can only happen at a few biomed companies (which is where I'd put my checks if I were you), even when you have the DNA synthesis is very hard, in the "just don't bother before your PhD hard" realm, and they're even harder to handle without killing yourself. Bioweapons are not realistic.