Yes, technically you could notice the difference. You need spy in every AI city to calculate its science output precisely. You need to look for it to see which eurekas the AI have and which the AI doesn't (quite tricky job). And with all this info you're like "gotcha - I just saw what the tech with eureka required the same amount of science as the tech without eureka". But outside the world of flying pink unicorns you could never tell the difference. It's much more than that. With AI being too complex, it will always be 2-3 weeks behind actual gameplay rules. At some points it could be critical as development could just plainly stop without testing if complex AI will be unable to play with new rules. In the end you could just loose months of development on it. That's one of the points why modders could create more advanced AIs. Even if they change rules, they don't have large development team working on tight iterations.