Suggest removing reference to extension
It doesn't work as advertised - the $contact variable it provides is not the same so gives smarty errors if you're using it, and just having it installed whether you use $contact or not causes contact tokens to use the wrong contact for case emails. The latter could be a privacy issue they might not even notice.
The problem with telling people to install it is that there's a minimum hour of work that they'll spend even trying this out, and then trying to determine if it's a problem at their end or not. It's just creating more work for everyone, as opposed to spending the time just replacing $contact with a token.