I have a question about why signatures are enabled or disabled by default. I can understand that something like echo reply is disabled, because it could cause too many events, and is informational only. But a significant number of high-risk signatures is disabled by default, which makes me wonder why? does it have anything to-do with the fedility rating, meaning the signature might not be 100% trusted, or perhaps enabling everything will cause a resource shortage? Also, why is signatures retired? Is it simply because it is superseded?