Visual Assist build 2093 and newer
By default, VA Snippets with surrounding characters expand whether or not the current selection contains white space. You can make the surrounding work only if the current selection contains white space by setting the following in the registry:
HKCU\Software\Whole Tomato\Visual Assist X\<IDE spec>\SurroundWithSnippetOnCharIgnoreWhitespace2 = 00
Set to 01 to restore default behavior.