ISSUE-233: Provide rationale for bookmarking API section (7.4.3) [wsc-xit]

ISSUE-233: Provide rationale for bookmarking API section (7.4.3) [wsc-xit]

http://www.w3.org/2006/WSC/track/issues/233

Raised by: Thomas Roessler
On product: wsc-xit

>From LC-2255:

> Web user agents MUST NOT expose programmatic interfaces that allow bookmarking without explicit user consent.

Should the user agent not expose the API without consent, or should
the API not allow bookmarking without consent?

> Web user agents MUST NOT expose programmatic interfaces that allow bookmarking an URL that does not match the URL of the page that the user currently interacts with.

Why not?