I got a little fired up by my previous find on using FIELD for declaring global variables in a Page. Therefore I did a little more digging.
FIELD-declared variables does not leak into embedded views, nor do FIELD-declared variables in view selection leak up to the containing page.
FIELD-declared variables leak down to an embedded outline when you display a page in the Notes Client and on the web, HTML style. If you show the embedded outline using a Java Applet, it doesn't work.
FIELD-declared variables in an outline are globally available to the items below the outline item it's declared in (regardless of indentation), in the Notes Client. They are not globally available for web applications, regardless of HTML/Java rendering. E.g. outline item 1 has a FIELD-declared variable -> every outline item after outline item 1 can use it (Notes only).