Hmm, as far as I know, AI can use your ships if they have the tech for that and it's better than others.

That would be indeed interesting to fight my own designs. I wonder what would happen to deleted designs, too - I often delete some depending on tech development since I hate to clog up my shipyard with designs I won't use.

Could the AI use a design I scrapped a few turns ago ? (it should be able to regardless if it uses player designs I'd guess).

Fascinating. Were you seeing that before the spy units came into the game?

It sounds like the computer is using a banked spy unit to scan your empire, which is sweet if it's true. I've had some sympathy with folks who talk about the "cheese" factor of looking at a planet in spy placement mode without actually placing a spy. But if the computer is doing it also, well, then it comes down to whether you can tell yourself an acceptable story about how that "really" works.