The weblogin system has been changed to fix a small security vulnerability, some websites that use the system in specific ways may be affected. We recommend that the webmasters of those sites take steps to fix the problem and use the system in the intended way. I'm sorry it took so long to fix this problem as I was unaware of the use case that caused it.
The List Server Usage Policy has been updated with some clarifications about weblogin. http://my.bzflag.org/w/List_Server_Usage_Policy