In our new MOSS07 farm, links to users (e.g. in membership lists, item
authors, etc.) aren't displaying their MySite. Instead they display
the generic WSS userinfo page. Looking at the component responsible
for handling that link ultimately revealed that a method on
Microsoft.SharePoint.Utilities.SPUtility called RedirectValidate() was
rejecting the redirect request to the different web app.

At first I thought that it was an issue with the personal site
settings for the SSP, but playing with the method further (see test
code below), I can't seem to get it to accept *any* absolute URL with
a different host than the current web context, regardless of whether
its in the farm, a Public AAM url, a "trusted personal site" as
configured in the SSP, .... I'm at a loss to understand what policies
it's applying, there's no documentation, etc. And of course meanwhile
it's breaking our ability to link to user profiles.

Has anyone run into this behavior before?