svn settings overwritten by fabric

It appears that fabric is overwriting my local svn user settings. The main bit of code that I can think of that would matter is:

env.svnuser = 'redmine'
env.svnpass = 'SomePassword'

So this sets env.svnuser and env.svnpass, and they are then used on the remote server (using sudo).

However when I next run svn locally, it appears that svn is using the username set by fabric - the stored subversion user in ~/.subversion/auth/svn.simple is replac开发者_JAVA技巧ed with the value set in env.svnuser. Any idea how this could happen?

fabric does have svn-specific code, and 'svn' string never occurs in fabric sources (at least as of 1.0.0).