When changing the URl Rewrite settings in IIS Manager (and maybe with simple file edit) the running URL Rewrite configuration isn't refreshed until the IIS doesn't get a full restart or the actual AppPool doesn't get recycled.
IIS version: 7.5 (WIndows 7 x64), URL Rewrite version: 2.0
Similar issue on Stack Overflow: IIS 7.5. Can't disable Url Rewriting rules (I deleted rules but they still affect)