Conditional Button Label

Adobe changes the label of  the download button depending upon what options are selected.

The default selection includes both Adobe Reader and the Google Toolbar.  The button label helped alert me to the fact that the option for the Toolbar was selected by default:

   

When I de-selected the Toolbar option, the button label dynamically changed:

Though I would have preferred not to have the Toolbar selected by default,  this seems to be an effective strategy for preventing unwanted consequences where users must "opt out" of pre-selected items.