What would you say about?
```ruby
    def request.not_xhr?; not xhr?; end
    default_message = if request.not_xhr?
                        _('Invalid parameters sent. You may have mistyped the address. If you continue having trouble with this, please contact an Administrator.')
                      else
                        _('Invalid parameters sent in the request for this operation. Please contact a system administrator.')
                      end
```
just kidding :smiling_imp: